Solaris Naming Setup and Configuration Guide

Chapter 13 Setting Up DNS Servers

This chapter describes how to set up a Domain Name System (DNS) name server.

"Creating the resolv.conf File" and "Setting Up the resolv.conf File"

Setting Up DNS Servers

To set up a DNS server:

Set the server up as a DNS client (this includes setting up the server's resolv.conf file.

See Chapter 12, Setting Up DNS Clients.

Set up the boot file.

See "Setting Up the Boot File".

Set up the data files

See "Setting Up the Data Files". Four data files have to be set up:
1. The named.ca file.
  
  See "Setting Up the named.ca File".
2. The hosts file.
  
  See "Setting Up the hosts File".
3. The hosts.rev file.
  
  See "Setting Up the hosts.rev File".
4. The named.local file.
  
  See "Setting Up the named.local File".

Initialize the server.

See "Initializing the Server".

Test the server.

See "Testing Your Installation".

Note -
The most common use of DNS is to connect your network to the global Internet. In order to connect to the Internet, your network IP address must be registered with whomever is administering your parent domain. Who that administrator is varies according to your geographic location and type of parent domain. This manual does not describe how to register networks with domain administrators.

Server Boot and Data File Names

To function correctly, the in.named daemon requires a boot file and four data files.

Caution -

The IP addresses and network numbers used in examples and code samples in this manual are for illustration purposes only. Do not use them as shown because they may have been assigned to an actual network or host.

Boot File

The master server boot file is /etc/named.boot. (See "Setting Up the Boot File".) The boot file contains a list of domain names and the file names containing host information. (See Solaris Naming Administration Guide for additional information on the named.boot file.)

Names of DNS Data Files

So long as you are internally consistent, you can name the zone data files anything you want. This flexibility may lead to some confusion when working at different sites or referring to different DNS manuals and books.

For example, the file names used in Sun manuals and at most many Solaris sites vary from those used in the book DNS and BIND by Albitz and Liu, O'Reilly & Associates, 1992, and both of those nomenclatures have some differences from that used in the public-domain Name Server Operations Guide for BIND, University of California.

In addition, this manual and other DNS documentation uses generic names that identify a file's main purpose, and specific example names for that file in code record samples. For example, Solaris Naming manuals use the generic name hosts when describing the function and role of that file, and the example names db.doc and db.sales in code samples.

For reference purposes, Table 13-1 compares BIND file names from these three sources:

Table 13-1 File Name Examples


Solaris Names	O'Reilly Names or other names	U.C. Berkeley Names	Content and Purpose of File
`/etc/named.boot`	`/etc/named.boot`	`/etc/named.boot`	The boot file specifies the type of server it is running on and the zones over which it has control. It contains a list of domain names and the names of the data files.
`/etc/resolv.conf`	`/etc/resolv.conf`	`/etc/resolv.conf`	This file resides on every DNS client (including DNS servers) and designates the servers which the client queries for DNS information.
`named.ca`	`db.cache` `db.root`	`root.cache`	This file establishes the names of root servers and lists their addresses.
Generic: `hosts` Examples: `db.doc db.sales`	Generic: `db.domain` Examples: `db.movie` `db.fx`	Generic: `hosts` Example: `ucbhosts`	This file contains all the data about the machines in the local zone that the server serves.
Generic: `hosts.rev` Examples: `doc.rev`	Generic: `db.ADDR Examples: db.192.249.249 db.192.249.253`	`hosts.rev`	This file specifies a zone in the `in-addr.arpa.` domain, a special domain that allows reverse (address-to-name) mapping.
`named.local`	Generic: `db.cache` Example: `db.127.0.0`	`named.local`	This file specifies the address for the local loopback interface, or localhost
`$INCLUDE` files	`$INCLUDE` files	`$INCLUDE` files	Any file identified by an `$INCLUDE()` statement in a data file.

Data Files

The four required data files are:

/var/named/named.ca. (See "Setting Up the named.ca File" and Solaris Naming Administration Guide for additional information on the named.ca file.) So long as you are internally consistent, you can name this file anything you want.

/var/named/hosts. (See "Setting Up the hosts File" and Solaris Naming Administration Guide for additional information on hosts files.)

The name hosts is a generic name indicating the file's purpose and content. But to avoid confusion with /etc/hosts, you should name this file something other than hosts. The most common naming convention is db.domainname. Thus, the hosts file for the doc.com domain would be called db.doc.

If you have more than one zone, each zone must have its own hosts file and each of these zone hosts files must have a unique name. For example, if your DNS domain is divided into doc.com and sales.doc.com zones, you could name one hosts file db.doc and the other db.sales.

/var/named/hosts.rev. See "Setting Up the hosts.rev File" and Solaris Naming Administration Guide for additional information on the hosts.rev file.)

The name hosts.rev is a generic name indicating the file's purpose and content. If you have more than one zone, each zone must have its own hosts.rev file and each of these zone hosts.rev files must have a unique name. For example, if your DNS domain is divided into doc.com and sales.doc.com zones, you could name one hosts.rev file doc.rev and the other sales.rev.

/var/named/named.local. See "Setting Up the named.local File" and Solaris Naming Administration Guide for additional information on the named.local file.) So long as you are internally consistent, you can name this file anything you want.

`$INCLUDE` Files

An include file is any file named in an $INCLUDE() statement in a DNS data file. $INCLUDE files can be used to separate different types of data into multiple files for your convenience. (See Solaris Naming Administration Guide for additional details.)

Domain Names

A domain name is the name assigned to a group of systems on a local network that share DNS administrative files. A domain name is required for the network information service database to work properly.

Default Domain Name

DNS obtains your default domain name from your resolv.conf file.

If the resolv.conf file is not available, or does not identify a default domain, and if your enterprise-level name service is either NIS+ or NIS, the Sun implementation of DNS obtains the default domain name from those services.

If resolv.conf is not available or does not provide a domain name and you are not running either NIS+ or NIS, you must either provide a resolv.conf file on each machine that does specify the domain , (see "Setting Up the resolv.conf File"), or set the LOCALDOMAIN environment variable.

Trailing Dots in Domain Names

When working with DNS-related files, follow these rules regarding the trailing dot in domain names:

Use a trailing dot in domain names in hosts, hosts.rev, named.ca, and named.local data files. For example, sales.doc.com. is correct for these files.

Do not use a trailing dot in domain names in named.boot or resolv.conf files. For example, sales.doc.com is correct for these files.

Setting Up the `resolv.conf` File

A simple example resolv.conf file for a server in the doc.com domain is shown below:

Example 13-1 Sample `resolv.conf` File for DNS Server

;
; /etc/resolv.conf file for dnsmaster (sirius)
;
domain             doc.com
nameserver         0.0.0.0
nameserver         111.22.3.5

The first line of the /etc/resolv.conf file lists the domain name in the form:

domain domainname

Where domainname is the name registered with the Internet governing bodies (as of this writing, the InterNIC).

Note -

No spaces or tabs are permitted at the end of the domain name. Make sure that you enter a hard carriage return immediately after the last character of the domain name.

The second line identifies the server itself in the form:

nameserver 0.0.0.0

Succeeding lines list the IP addresses of one or two secondary or cache-only name servers that the resolver should consult to resolve queries. Name server entries have the form:

nameserver IP_address

Where IP_address is the IP address of a secondary or cache only DNS name server. The resolver queries these name servers in the order they are listed until it obtains the information it needs.

Setting Up the Boot File

The contents of the boot file varies, depending on the type of server. This section describes boot files for primary, secondary, and caching-only servers.

Note -

The boot file must be called named.boot. The server's initialization script, /etc/init.d/inetsvc, expects to find /etc/named.boot when it looks for the in.named daemon boot file. The script will not start the daemon if you name the boot file anything else.

Example 13-2 Example Master Boot File for a Primary Server

; named.boot file on the dnsmastr
; 
; files required by in.named are located here
directory /var/named
; here are the names of the primary files
cache      .                              named.ca
primary    doc.com                        db.doc
primary    0.0.127.in-addr.arpa           db.127.0.0
primary    6.45.123.in-addr.arpa          db.123.45.6
;This system is also the secondary for the sales.doc.com domain
secondary  sales.doc.com                  111.22.3.4 db.sales
secondary  3.22.111.in-addr.arpa          111.22.3.4 db.192.168.8

In the context of the various example files presented in this chapter, the sample boot file above corresponds to the boot file of the dnsmaster, server which is an alias for the altair machine whose IP address is 123.45.6.1.

A boot file contains three elements:

A directory line (see "The directory Line").
A cache line (see "The cache Line").
One or more name server lines (see "Specifying Server Function").

The `directory` Line

The directory line in the boot file designates the directory in which you want the name server to run:

directory /var/named

This allows the use of relative path names for the files mentioned in the boot file or, later, with the $INCLUDE directive. This feature is especially useful if you have many files to be maintained, and you want to locate them all in one directory dedicated to that purpose.

If there is no directory line in the boot file, all file names listed in the boot file must be full path names.

The `cache` Line

A name server needs to know which servers are the authoritative name servers for the root zone. To do this, you have to list the addresses of these higher authorities.

All servers should have the following line in the boot file to find the root name servers:

cache    .     named.ca

The first field after cache (.) indicates that the server will obtain root servers hints from the indicated file, in this case, named.ca (located in the directory /var/named).

The Server Role Lines

The server role lines specify whether the server is a primary and secondary name server as described in "Specifying Server Function", below.

Specifying Server Function

DNS servers perform one or more functions:

Zone primary master server. Each zone has one server that is designated as the primary master server for that zone. A zone's primary master server is the authoritative server for that zone. (See "Specifying a Primary Master Server".)

Zone secondary master server. A zone may have one or more secondary master servers. Secondary master servers obtain their DNS from the zone's primary master server. You do not modify data files on a secondary server; you modify the data files on the zone's primary server and the secondary servers update their files from the primary. (See "Specifying a Secondary Master Server".)

Caching-Only Server. All servers are caching servers in the sense that they all maintain a cache of DNS data. A caching-only server is a server that is not a master server for any zone other than the in-addr.arpa. domain. (See "Specifying a Cache-Only Server".)

Root Domain servers. If your network is connected to the Internet, your root domain servers are out on the Internet itself and all you have to do is provide their Internet IP addresses in the named.ca file, as explained in "Setting Up the named.ca File". If your network is not connected to the Internet, you have to set up your own root domain server, as explained in "Setting Up a Non-Internet Root Master".

These various server functions can be performed by the same machine. For example, a machine can be a primary master server for one zone and a secondary master server for another zone. When this manual refers to a primary, secondary, or caching-only server, it is not referring to a particular machine, but the role that machine plays for a given zone.

Refer to Solaris Naming Administration Guide for additional information on these different server functions.

Specifying a Primary Master Server

To specify that a server is the primary server for a given zone, you create three primary records in that server's named.boot file:

Create the primary record for the zone.

This record designates the server as a primary server for the zone and tells the server where to find the authoritative hosts file. A "primary" record has three fields:
- The first field designates the server as "primary."
- The second field identifies the zone it serves.
- The third field identifies the hosts file.
For example, the following line in a boot file specifies that the server is the primary server for the doc.com zone, using authoritative data from the file db.doc:
primary doc.com db.doc

Create a primary record for the zone's reverse map.

This record designates the server as a primary server for the zone's reverse address map (that is, the reverse address domain for doc.com), and tells the server where to find the authoritative hosts file. This record has three fields; the first field designates the server as "primary," the second field identifies the zone, and the third field identifies the hosts.rev file.

The reverse address domain for a zone is the composed by the zone's IP address in reverse order followed by in-addr.arpa. For example, suppose that the doc.com zone's IP address is 123.45.6. In that case, the reverse address domain would be 6.45.123.in-addr.arpa.

Thus, the following line in a boot file specifies that the server is the primary server for the reverse address domain of the doc.com zone, using authoritative data from the file doc.rev:
primary 6.45.123 . in-addr.arpa doc.rev

Create a primary record for the reverse address of the local loopback interface or host.

This record designates the server as a primary server for the loopback host, and tells the server where to find the authoritative hosts file. This record has three fields, the first field designates the server as "primary," the second field identifies the loopback host reverse address, and the third field identifies the hosts file.

Loopback hosts are always identified as 0.0.127.in-addr.arpa.

Thus, the following line in a boot file specifies that the server is the primary server for the reverse address domain of the loopback host using authoritative data from the file named.local:
primary 0.0.127.in-addr.arpa named.local

Specifying a Secondary Master Server

To specify that a server is to be the secondary server for a given zone, you create "secondary" records in that server's named.boot file. Separate records can designate the server as a secondary server for the zone, the zone's reverse address domain, and the loopback host.

A "secondary" record has three required fields:

The first field designates the server as "secondary."
The second field identifies the zone it serves.
The third field identifies the IP address of the primary server for the zone from which the secondary server obtains its authoritative data.

A "secondary" record may have one or more optional fields after the required fields. The optional fields are:

Secondary servers. After the IP address of the primary server, you can add IP addresses of other secondary servers. These provide additional sources from which the secondary server can obtain data. Adding IP addresses of secondary servers may under some circumstances reduce performance, unless those IP addresses are additional network addresses of a multihome primary server.

Backup file. After the IP address of the primary (and optional secondary) server(s), you can add the name of a backup hosts file. If a backup file name is present, the secondary server loads its data from that file, then checks with the primary (and optional secondary) servers to make sure that the data in the backup file is up to date. If the backup file is not up to date, it is brought up to date, based on the information received from the primary server.

For example, the following lines in a boot file specify that the server is the secondary server for the doc.com zone and its reverse address domain; that it obtains its authoritative data from the primary server with an IP address of 129.146.168.119, that it uses the server 192.146.168.38 as a secondary source of zone data, and initially loads its data from the file doc.com.bakup:

 
secondary   doc.com   129.146.168.119  192.146.168.38  doc.com.bakup
secondary   4.0.32.128.in-addr.arpa       129.146.168.119

In the context of the various example files presented in this chapter, the sample boot file lines above correspond to the boot file of the dnssecondary server, which is an alias for the sirius machine whose IP address is 192.146.168.38.

Note -

A server may act as the primary server for one or more zones, and as the secondary server for one or more zones. The mixture of entries in the boot file determines whether a server is a primary or secondary server for a given zone

Specifying a Cache-Only Server

A cache-only server does not maintain any authoritative data; it handles queries and asks the hosts listed in the in.named file for the information needed. In other words, a cache-only server handles the same kind of queries that authoritative name servers perform but it does not maintain any authoritative data itself.

Example 13-3 is a sample boot file for a caching-only server.

Example 13-3 Sample Master Boot File for Caching-only Server

;
; Sample named.boot file for caching-only name server
;
; type                  domain                 source file or host
;
directory /var/named
cache                   .                      named.ca
primary                 0.0.127.in-addr.arpa   named.local

You do not need a special line to designate a server as a cache-only server. What denotes a cache-only server is the absence of any secondary or primary authority lines in the boot file, except as noted below.

A cache-only server requires:

A directory line in the boot file
A primary 0.0.127.in-addr.arpa line in the boot file
A cache . named.ca line in the boot file

Setting Up the Data Files

All the data files used by the DNS daemon in.named are written in standard resource record format. Each line of a file is a record, called a resource record (RR). Each DNS data file must contain certain resource records.

See Solaris Naming Administration Guide for a description of resource records, their formats, the fields they contain, special characters, and control entries.

Resource Record Types

The most commonly used types of resource records are listed in Table 13-2. They are usually entered in the order shown in Table 13-2, but that is not a requirement.

Table 13-2 Commonly Used Resource Record Types


Type	Description
SOA	start of authority
NS	name server
A	Internet address (name to address)
PTR	pointer (address to name)
CNAME	canonical name (nickname)
TXT	text information
MX	mail exchanger

See Solaris Naming Administration Guide for detailed descriptions of these Resource Record types.

In the sample files included in the following sections, @ indicates the current zone or origin and lines that begin with a semicolon (;) are comments.

Setting Up the `named.ca` File

he root servers. Root server names are indicated in the NS record and addresses in the A record. You need to add an NS record and an A record for each root server you want to include in the file.

How you obtain or create your named.ca file depends on whether or not your network is connected to the world Internet.

Internet `named.ca` File

If your network is connected to the Internet, at the present time you obtain your named.ca file from InterNIC registration services via:

Anonymous FTP. The FTP site is: ftp.rs.internic.net. The file name is: /domain/named.root.

Gopher. The Gopher site is: rs.internic.net. The file is: named.root, which can be found under the InterNIC Registration Services menu, InterNIC Registration Archives submenu.

If you are following the naming conventions used in this manual, you then move named.root to /var/named/named.ca.

Example 13-4 Example Internet `named.ca` file

;
; formerly NS1.ISI.EDU
.                        3600000    NS   B.ROOT-SERVERS.NET.
B.ROOT-SERVERS.NET.      3600000    A    128.9.0.107
;
; formerly C.PSI.NET
.                        3600000    NS   C.ROOT-SERVERS.NET.
C.ROOT-SERVERS.NET.      3600000    A    192.33.4.12
;
; formerly TERP.UMD.EDU
.                        3600000    NS   D.ROOT-SERVERS.NET.
D.ROOT-SERVERS.NET.      3600000    A    128.8.10.90
;
; formerly NS.NASA.GOV
;.                       3600000    NS   E.ROOT-SERVERS.NET.
E.ROOT-SERVERS.NET.      3600000    A    192.203.230.10
;
; formerly NS.ISC.ORG
.                        3600000    NS   F.ROOT-SERVERS.NET.
F.ROOT-SERVERS.NET.      3600000    A    192.5.5.241
;
; formerly NS.NIC.DDN.MIL
.                        3600000    NS   G.ROOT-SERVERS.NET.
G.ROOT-SERVERS.NET.      3600000    A    192.112.36.4
;
; formerly AOS.ARL.ARMY.MIL
.                        3600000    NS   H.ROOT-SERVERS.NET.
H.ROOT-SERVERS.NET.      3600000    A    128.63.2.53
;
; formerly NIC.NORDU.NET
.                        3600000    NS   I.ROOT-SERVERS.NET.
I.ROOT-SERVERS.NET.      3600000    A    192.36.148.17
;
; temporarily housed at NSI (InterNIC)
.                        3600000    NS   J.ROOT-SERVERS.NET.
J.ROOT-SERVERS.NET.      3600000    A    198.41.0.10
;
; temporarily housed at NSI (InterNIC)
.                        3600000    NS   K.ROOT-SERVERS.NET.
K.ROOT-SERVERS.NET.      3600000    A    198.41.0.11
;
; temporarily housed at ISI (IANA)
.                        3600000    NS   L.ROOT-SERVERS.NET.
L.ROOT-SERVERS.NET.      3600000    A    198.32.64.12
;
; temporarily housed at ISI (IANA)
.                        3600000    NS   M.ROOT-SERVERS.NET.
M.ROOT-SERVERS.NET.      3600000    A    198.32.65.12
; End of File

Non-Internet `named.ca` File

If your network is not connected to the Internet, you create your own named.ca file. To do this, you designate one of your servers to be your root server, then create a named.ca file on every DNS server pointing to that root server.

For example, suppose your domain is named private and you designate the machine ourroot as your non-Internet root server. The ourroot machine has an IP address of 192.1.1.10. Your named.ca files would then contain the line:

ourroot.private.  999999  IN  A  192.1.1.10

Cache files also need an SOA record, NS records for each domain and subdomain, and A records for each server.

For example, suppose that in addition to ourroot you also had DNS name servers called ourprimary and oursecondary. The named.ca files on all of your DNS servers would then look like this:

Example 13-5 Sample `named.ca` File (Non-Internet)

;
@    IN    SOA  ourroot.private.   hermit.ourroot.private  (    
                 1997071401       ;  serial number (YYYYMMDD##)
                 10800            ;  refresh after 3 hours
                 3600             ;  retry after 1 hour
                 604800           ;  expire after 1 week
                 86400 )          ;  minimum TTL of 1 day
;
ourroot.private.      999999     IN    A    192.1.1.10
;
private.                         IN    NS   ourprimary.private.
1.1.192.in-addr.arpa             IN    NS   ourprimary.private.
ourprivate.private.              IN    A    192.1.1.1
;
private.                         IN    NS   oursecondary.private.
1.1.192.in-addr.arpa             IN    NS   ourseconary.private.
oursecondary.private.            IN    A    192.1.1.2

See "Setting Up a Non-Internet Root Master" for a more complete discussion of setting up a domain that is not connected to the Internet.

Setting Up the `hosts` File

The hosts file contains all the data about every machine in your zone. If a zone covers more than one domain, all machines in all the domains covered by the zone are listed in the zone's host file (see "Setting Up Subdomains--Same Zone").

Note -

The name hosts is a generic name indicating the file's purpose and content. But to avoid confusion with /etc/hosts, you should name this file something other than hosts. If you have more than one zone, each zone must have its own hosts file and each of these zone hosts files must have a unique name. For example, if your DNS domain is divided into doc.com and sales.doc.com zones, you could name one hosts file db.doc and the other sales.db.doc.

There must be a separate, uniquely named, hosts file for each zone. If you have more than one zone, each zone's host file must include information about the master (primary and secondary) servers of the other zones as described in "Setting Up Subdomains--Different Zones".

Example 13-6 Sample `hosts` File

;
; SOA rec
doc.com  IN SOA sirius.doc.com sysop.centauri.doc.com (
                 1997071401       ;  serial number (YYYYMMDD##)
                      10800       ;  refresh every 3 hours
                      10800       ;  retry every 3 hours
                      604800      ;  expire after a week
                      86400 )     ;  TTL of 1 day
; Name Servers
doc.com                   IN  NS  sirius.doc.com
sales.doc.com             IN  NS  altair.sales.doc.com
; Addresses
localhost                 IN  A  127.0.0.1
sirius                    IN  A  123.45.6.1
rigel                     IN  A  123.45.6.112
antares                   IN  A  123.45.6.90
polaris                   IN  A  123.45.6.101
procyon                   IN  A  123.45.6.79
tauceti                   IN  A  123.45.6.69
altair.sales.doc.com      IN  A   111.22.3.4
; aliases
durvasa                   IN  CNAME sirius.doc.com
dnsmastr                  IN  CNAME sirius.doc.com
dnssales                  IN  CNAME altair.sales.doc.com

A hosts file usually contains five elements:

A Start of Authority (SOA) record

One or more Name Server (NS) records identifying primary and secondary DNS name servers

Address (A) records for each host in the zone

Canonical Name (CNAME) records for each host alias in the zone

One or more Mail Exchange (MX) records

(See Solaris Naming Administration Guide for detailed descriptions of these resource record types.)

Setting Up the `hosts.rev` File

The hosts.rev file sets up inverse mapping.

Note -

The name hosts.rev is a generic name indicating the file's purpose and content. If you have more than one zone, each zone must have its own hosts.rev file and each of these zone hosts.rev files must have a unique name. For example, if your DNS domain is divided into doc.com and sales.doc.com zones, you could name one hosts.rev file doc.rev and the other sales.rev.

Example 13-7 Sample `hosts.rev` File

; SOA rec
6.45.123.in-addr.arpa.  IN SOA sirius.doc.com sysop.centauri.doc.com (
                 1997071401       ;  serial number (YYYYMMDD##)
                      10800       ;  refresh every 3 hours
                      10800       ;  retry every 3 hours
                      604800      ;  expire after a week
                      86400 )     ;  TTL of 1 day
; Name Servers
6.45.123.in-addr.arpa.   IN  NS  sirius.doc.com
1                        IN  PTR sirius.doc.com

A hosts.rev file contains three elements:

A Start of Authority (SOA) record

One or more Name Server (NS) records identifying primary and secondary DNS name servers. Server names should be fully qualified.

A PTR record for each host in the zone. Machine names should be fully qualified.

(See Solaris Naming Administration Guide for detailed descriptions of these resource record types.)

Setting Up the `named.local` File

The named.local file sets up the local loopback interface for your name server.

Example 13-8 Sample `named.local`File

; SOA rec
0.0.127.in-addr.arpa. IN SOA sirius.doc.com sysop.centauri.doc.com (
                          1997071401       ;  serial number (YYYYMMDD##)            
                           10800           ;  refresh every 3 hours
                           10800           ;  retry every 3 hours
                           604800          ;  expire after a week
                           86400 )         ;  TTL of 1 day
; Name Servers
0.0.127.in-addr.arpa.      IN  NS     sirius.doc.com
1                          IN  PTR  localhost.

A named.local file contains three elements:

A Start of Authority (SOA) record, which indicates the start of a zone and includes the name of the host on which the named.local data file reside.

One or more Name Server (NS) records identifying primary and secondary DNS name servers. Server and domain names should be fully qualified.

A PTR record for localhost

(See Solaris Naming Administration Guide for detailed descriptions of these resource record types.)

Initializing the Server

To initialize a server:

Install the named.boot boot file and the required data files as described in the previous sections.

Run in.named.
# /usr/sbin/in.named
Instead of running in.named from the command line, you can reboot.

Testing Your Installation

After your boot and data files are set up and in.named running, test your installation as follows:

Check your syslog file for error messages.

See Solaris Naming Administration Guide for common DNS error messages and troubleshooting information.

Look up a host name in the local domain with nslookup.
dnsmaster% nslookup altair Server: dnsmaster.doc.com Address: 192.146.168.5 Name: altair.doc.com Address: 192.146.168.10
- If you get a successful result, your name server is probably functioning correctly.
- If you get a "Can't find," or "can't initialize address," type of message for your server, or a "Non-existent domain," type message, it may mean that your server is not correctly listed in the boot or hosts files.
- If you get a "can't find name" or "Non-existent domain" type of message, it may mean that the host you looked up is not in the server's hosts file, or the domain is incorrectly set in resolv.conf, or there is some other server problem.

Look up a remote domain name with nslookup.

If your network is connected to the Internet, look up the name of a remote domain. (If your network is not connected to the Internet, look up the name of a subdomain in another zone, if you have one.) For example, to look up the name of the remote internic.net Internet domain, you would enter:
dnsmaster% nslookup internic.net Server: dnsmaster.doc.com Address: 192.146.168. Name: internic.net Addresses: 198.41.0.9, 198.41.0.6, 198.41.0.5, 198.41.0.8
- If you get a successful result, your name server is probably functioning correctly.
- If the above command does not find the remote domain name, one possible cause is that your network's connection to the Internet is not functioning properly.
- Another possible cause is that your named.ca file is not properly installed or set up.
(The second time you use nslookup to find a domain, your answer will be returned as "non-authoritative". This is normal because the answer is now coming from your cache, not the remote name server.)

Look up a host name in your domain from a remote domain.

If your network is connected to the Internet, look up the name of a host in your domain from a remote domain. (If your network is not connected to the Internet, look up the name of a host in your domain from another zone, if you have one.)

For example, to look up the name of host in your domain from a remote Internet domain, you would enter two arguments after the nslookup command: First the name of the host you are searching for, and second, the name of the name server you are testing:
remotemachine9% nslookup altair remotemaster.foo.org. Server: remotemaster.foo.org Address: 123.231.12.22 Name: altair.doc.com Addresses: 111.22.3.4
- If you get a successful result, your name server is probably functioning correctly.
- If the above command does not find the machine you are searching for, one possible cause is that your domain is not properly registered with whomever is administering the parent domain (.com in the above example).

Setting Up Subdomains

Same zone. The easiest method is to include the subdomain in the parent domain's zone. In this way, one set of DNS servers and data files cover all the machines regardless of their domain. See "Setting Up Subdomains--Same Zone".

The advantage of the same-zone method is simplicity and ease of administration. The disadvantage is that one set of servers has to serve all machines in all of the zone's domains. If there are too many machines, the servers will be overloaded and network performance may decline.

Different zones. You can place different domains in different zones. This is more complex because you have to specify how clients in one zone obtain DNS information about hosts in another zone. See "Setting Up Subdomains--Different Zones".

The advantage of the different-zone method is that you can assign different sets of servers to serve machines in different domains; in that way, you spread out server load so that no group of servers is overloaded. The disadvantage is that setup maintenance is more complicated.

Setting Up Subdomains--Same Zone

Data files for multi-domain zones must include records for all machines and servers in each domain covered by the zone.

Setting up a multi-domain zone is the same as setting up a zone with a single domain, except that fully qualified domain names are used in the hosts file to identify machines in remote domains. In other words, in the hosts file, when you identify a machine in the server's local domain, you only need to use the machine's name. But when you identify a machine in some other domain, you must identify the machine with a fully qualified domain name in the format: machine.domain.

Server and machine names in hosts.rev and named.local files also need to be fully qualified with domain names. But that is true regardless of whether or not the zone has more than one domain.

Setting Up Subdomains--Different Zones

Setting up subdomains that are in different zones is more complicated than including multiple domains in a single zone, because you have to specify how clients in different zones obtain DNS information from the other zones.

When you divide a network into multiple domains, you do so by creating a domain hierarchy. That is, one domain is the top domain. Beneath the top domain, you create one or more subdomains. If you want, you can create subdomains of subdomains. But every subdomain has a set place relative to the top domain in the hierarchy of domains. When read from left to right, domain names identify the domain's place in the hierarchy. For example, the doc.com domain is above the sales.doc.com domain, while the west.sales.doc.com domain is below the sales.doc.com domain.

DNS zones acquire a hierarchy from the domains that they contain. The zone containing a network's top domain is the top zone. A zone that contains one or more subdomains below the top domain is below the top zone in the zone hierarchy. When DNS information has to be passed from one zone to another, it is passed up and down the zone hierarchy. This means that each zone has to have records in its data files specifying how to pass information up to the zone immediately above it, and down to any zones immediately below it.

To correctly transfer DNS information from one zone to another in a multi-zone network:

hosts.rev file. There must be a PTR record in each hosts.rev file pointing to the name of one or more master servers in the zone immediately above it. This type of PTR record is exactly the same as any other PTR record in the file, except that it identifies a server in the zone above.
hosts file NS records. There must be a zone NS record in each hosts file identifying each name server in each zone immediately below. This type of NS record has to have the name of the zone below as the first field in the NS record. (The name of the zone is specified in the SOA record of the zone's host file.)
hosts file A records. There must be an A record in each hosts file identifying the IP address of each name server in each zone immediately below. This type of A record has to have the name of the zone below as the first field in the A record. (The name of the zone is specified in the SOA record of the zone's host file.)

The example files in "A Practical Example" illustrate a network with two zones.

Setting Up a Non-Internet Root Master

If your network is connected to the Internet, your root domain server exists at the root domain Internet site; all you have to do is provide that site's Internet IP addresses in your cache file, as explained in "Internet named.ca File".

If your network is not connected to the Internet, you must set up primary and secondary name servers in the root-level domain on your local network. This enables all domains in your network to have a consistent authoritative server to which to refer; otherwise, machines may not be able to resolve queries.

For example, suppose your non-Internet domain is named private and you designate the machine ourroot as your root server. The ourroot machine has an IP address of 192.1.1.10. You would then perform the following steps:

Create named.ca files on your primary master servers that point to your own root server.

For example:
ourroot.private. 999999 A 192.1.1.10
A named.ca file must also contain NS records for each internal domain and subdomain and A records for each server as described in "Setting Up a Non-Internet Root Master".

Add a cache resource record for the root domain to the boot files of all DNS name servers on your network.

For example:
cache . named.ca
(See "Boot File"for more information.)

Remove the root domain cache resource record from the boot file of your root server.

In other words, delete the cache . named.ca line from ourroot's boot file.

Insert a primary line for the root domain in the root server's boot file.

For example, in ourroot's boot file you would add the line:
primary . ourroot.private
Caution -
If you later decide to connect your network to the Internet, you must replace all the named.ca files on all of your servers with the current Internet files and replace the primary . rootserver line with a cache . named.ca line in the former root server's boot file.

A Practical Example

This section shows the files that would be needed to implement DNS for a sample Internet-connected network based on the examples used in this chapter.

Caution -

This practical example assumes:

An environment connected to the Internet

Two networks, each with its own domain (doc.com and sales.doc.com) and its own DNS zone

Thedoc.com domain and zone is the top zone over the sales.doc.com subdomain and zone.

Each network has its own network number

Table 13-3 Example Network Domain and Zone Configuration


Name and Zone	Number
`doc.com`	`123.45.6`
`sales.doc.com`	`111.22.3`

Each zone has a master and one secondary server, and the secondary server of sales.doc.com is also the primary server of doc.com:

Table 13-4 Example Network DNS Servers


Zone	Host Name	Function	Address	CNAME
`doc.com`	`sirius`	`primary` for `doc.com`	`123.45.6.1`	`dnsmaster`
`doc.com`	`deneb`	`secondary` for `doc.com`	`111.22.3.5`	dnssecond
`sales.doc.com`	`altair`	`primary` for `sales.doc.com`	`111.22.3.4`	`dnssales`
`sales.doc.com`	`altair`	`secondary`for sales.doc.com	`123.45.6.1`	dnsmaster

Example Boot Files

The following code examples show boot files for the three servers in the two networks:

Example 13-9 Example Boot File for `dnsmastr` Server

; named.boot file on the dnsmastr (sirius)
; 
; files required by in.named are located here 
directory /var/named
; here are the names of the primary files
cache         .                         named.ca
primary       doc.com                   db.doc
primary       0.0.127.in-addr.arpa      named.local
primary       6.45.123.in-addr.arpa     doc.rev
;This system is also the secondary for the sales.doc.com domain
secondary     sales.doc.com             111.22.3.4   db.sales
secondary     3.22.111.in-addr.arpa     111.22.3.4   sales.rev

Example 13-10 Example Boot File for `dnssales` Server

; named.boot file on the dnssales (altair)
; 
; in.named is located here
directory /var/named
; here are the names of the primary files
cache      .                        named.ca
primary    sales.doc.com            db.sales
primary    0.0.127.in-addr.arpa     db.127.0.0
primary    3.22.111.in-addr.arpa    db.192.168.8

Example 13-11 Example Boot File for `dnssecond` Server

; named.boot file on the dnsecond (deneb)
directory /var/named
cache           .               named.ca
secondary       doc.com         123.45.6.1 doc.com
secondary       6.45.123.in-addr.arpa    123.45.6.1 doc.123.45.6

Example `resolv.conf` Files

The following code examples show resolv.conf files for the three servers in the two networks. (If the host in question is not running in.named, the local host address should not be used as a name server.)

Example 13-12 Example `resolve.conf` File for `dnsmastr` Server

;
; /etc/resolv.conf file for dnsmaster (sirius)
;
domain           doc.com
nameserver       0.0.0.0
nameserver       111.22.3.5

Example 13-13 Example `resolve.conf` File for `dnssales` Server

;
; /etc/resolv.conf file for dnssales (altair)
;
domain           sales.doc.com
nameserver       111.22.3.4
nameserver       123.45.6.1

Example 13-14 Example `resolve.conf` File for `dnssecond` Server

;
; /etc/resolv.conf for dnssecond
;
domain           doc.com
nameserver       111.22.3.5
nameserver       123.45.6.1

Example `named.local` File

The following code example shows the named.local file used by the two primary servers on the two networks. Both servers have the same file.

Example 13-15 Example `named.local` File for Both Primary Servers

; SOA rec
0.0.127.in-addr.arpa. IN SOA siriusdoc.com. sysop.centauri.doc.com. (
                           19970331    ; serial number
                           10800       ; refresh every 3 hours
                           10800       ; retry every 3 hours
                           604800      ; expire after a week
                           86400 )     ; TTL of 1 day
; Name Servers
0.0.127.in-addr.arpa.  IN  NS   sirius.doc.com.
0.0.127.in_addr.arpa   IN  NS   dnssecond.doc.com
1  IN  PTR localhost.

Example `hosts` Files

The following code examples show db.doc and db.sales files for the two primary servers on the two networks.

Example 13-16 Example `db.doc` File for `dnsmastr` server

; SOA rec
doc.com.  IN SOA sirius.doc.com. sysop.centauri.doc.com. (
                           19970332    ; serial number
                           10800       ; refresh every 3 hours
                           10800       ; retry every 3 hours
                           604800      ; expire after a week
                           86400 )     ; TTL of 1 day
; Name Servers
doc.com.                IN  NS  sirius.doc.com.
sales.doc.com.          IN  NS  altair.sales.doc.com.
; Addresses
localhost               IN  A  127.0.0.1
sirius                  IN  A  123.45.6.1
rigel                   IN  A  123.45.6.112
antares                 IN  A  123.45.6.90
polaris                 IN  A  123.45.6.101
procyon                 IN  A  123.45.6.79
tauceti                 IN  A  123.45.6.69
altair.sales.doc.com.   IN  A   111.22.3.4
; aliases
dnsmastr                IN  CNAME    sirius.doc.com.
dnssecond.doc.com       IN  CNAME   deneb.doc.com

Example 13-17 Example `db.sales` File for `dnssales` server

; SOA rec
sales.doc.com.  IN SOA altair.sales.doc.com. sysop.polaris.doc.com. (
                           19970332    ; serial number
                           10800          ; refresh every 3 hours
                           10800          ; retry every 3 hours
                           604800        ; expire after a week
                           86400 )        ; TTL of 1 day
; Name Servers
doc.com.                IN  NS  sirius.doc.com.
sales.doc.com.          IN  NS  altair.sales.doc.com.
; Addresses
altair                  IN  A  111.22.3.4
localhost               IN  A  127.0.0.1
sirius.doc.com.         IN  A  123.45.6.1
luna                    IN  A  192.168.8.22
phoebus                 IN  A  192.168.8.24
deimos                  IN  A  192.168.8.25
ganymede                IN  A  192.168.8.27
europa                  IN  A  192.168.8.28
callisto                IN  A  192.168.8.29
; 
; aliases
dnssales.sales.doc.com  IN  CNAME    altair.sales.doc.com

Example `hosts.rev` Files

The following code examples show hosts.rev files for the two primary servers on the two networks:

Example 13-18 Example `doc.rev` File for `dnsmastr` server

; SOA rec
6.45.123.in-addr.arpa.  IN SOA sirius.doc.com. sysop.centauri.doc.com. (
                           19970331    ; serial number
                           10800       ; refresh every 3 hours
                           10800       ; retry every 3 hours
                           604800      ; expire after a week
                           86400 )     ; TTL of 1 day
; Name Servers
6.45.123.in-addr.arpa.  IN  NS  sirius.doc.com.
;Pointer records for 123.45.6
1                       IN  PTR sirius.doc.com.
112                     IN  PTR rigel.doc.com.
90                      IN  PTR antares.doc.com. 
101                     IN  PTR polaris.doc.com. 
79                      IN  PTR procyon.doc.com.
69                      IN  PTR tauceti.doc.com.

Example 13-19 Example `hosts.rev` File for `dnssales` Server

; SOA rec
3.22.111.in-addr.arpa.  IN SOA altair.sales.doc.com. sysop.polaris.doc.com. (
                           19970331    ; serial number
                           10800       ; refresh every 3 hours
                           10800       ; retry every 3 hours
                           604800      ; expire after a week
                           86400 )     ; TTL of 1 day
; Name Servers
3.22.111.in-addr.arpa.   IN  NS  altair.sales.doc.com.
;Pointer records for 111.22.3
22                       IN  PTR  luna
23                       IN  PTR  deneb
24                       IN  PTR  phoebus
25                       IN  PTR  deimos
26                       IN  PTR  altair
27                       IN  PTR  ganymede
28                       IN  PTR  europa
29                       IN  PTR  callisto

Example `name.ca` File

The following code example shows the named.ca file that is stored on each of the two primary servers on the two networks. Both servers use identical named.ca files.

Example 13-20 Example `named.ca` File

;
; formerly NS1.ISI.EDU
.                        3600000      NS    B.ROOT-SERVERS.NET.
B.ROOT-SERVERS.NET.      3600000      A     128.9.0.107
;
; formerly C.PSI.NET
.                        3600000      NS    C.ROOT-SERVERS.NET.
C.ROOT-SERVERS.NET.      3600000      A     192.33.4.12
;
; formerly TERP.UMD.EDU
.                        3600000      NS    D.ROOT-SERVERS.NET.
D.ROOT-SERVERS.NET.      3600000      A     128.8.10.90
;
; formerly NS.NASA.GOV
;.                       3600000      NS    E.ROOT-SERVERS.NET.
E.ROOT-SERVERS.NET.      3600000      A     192.203.230.10
;
; formerly NS.ISC.ORG
.                        3600000      NS    F.ROOT-SERVERS.NET.
F.ROOT-SERVERS.NET.      3600000      A     192.5.5.241
;
; formerly NS.NIC.DDN.MIL
.                        3600000      NS    G.ROOT-SERVERS.NET.
G.ROOT-SERVERS.NET.      3600000      A     192.112.36.4
;
; formerly AOS.ARL.ARMY.MIL
.                        3600000      NS    H.ROOT-SERVERS.NET.
H.ROOT-SERVERS.NET.      3600000      A     128.63.2.53
;
; formerly NIC.NORDU.NET
.                        3600000      NS    I.ROOT-SERVERS.NET.
I.ROOT-SERVERS.NET.      3600000      A     192.36.148.17
;
; temporarily housed at NSI (InterNIC)
.                        3600000      NS    J.ROOT-SERVERS.NET.
J.ROOT-SERVERS.NET.      3600000      A     198.41.0.10
;
; temporarily housed at NSI (InterNIC)
.                        3600000      NS    K.ROOT-SERVERS.NET.
K.ROOT-SERVERS.NET.      3600000      A     198.41.0.11
;
; temporarily housed at ISI (IANA)
.                        3600000      NS    L.ROOT-SERVERS.NET.
L.ROOT-SERVERS.NET.      3600000      A     198.32.64.12
;
; temporarily housed at ISI (IANA)
.                        3600000      NS    M.ROOT-SERVERS.NET.
M.ROOT-SERVERS.NET.      3600000      A     198.32.65.12
; End of File

Chapter 13 Setting Up DNS Servers

Setting Up DNS Servers

Server Boot and Data File Names

Boot File

Names of DNS Data Files

Data Files

$INCLUDE Files

Domain Names

Default Domain Name

Trailing Dots in Domain Names

Setting Up the resolv.conf File

Example 13-1 Sample resolv.conf File for DNS Server

Setting Up the Boot File

Example 13-2 Example Master Boot File for a Primary Server

The directory Line

The cache Line

The Server Role Lines

Specifying Server Function

Specifying a Primary Master Server

Specifying a Secondary Master Server

Specifying a Cache-Only Server

Example 13-3 Sample Master Boot File for Caching-only Server

Setting Up the Data Files

Resource Record Types

Setting Up the named.ca File

Internet named.ca File

Example 13-4 Example Internet named.ca file

Non-Internet named.ca File

Example 13-5 Sample named.ca File (Non-Internet)

Setting Up the hosts File

Example 13-6 Sample hosts File

Setting Up the hosts.rev File

Example 13-7 Sample hosts.rev File

Setting Up the named.local File

Example 13-8 Sample named.localFile

Initializing the Server

Testing Your Installation

Setting Up Subdomains

Setting Up Subdomains--Same Zone

Setting Up Subdomains--Different Zones

Setting Up a Non-Internet Root Master

A Practical Example

Example Boot Files

Example 13-9 Example Boot File for dnsmastr Server

Example 13-10 Example Boot File for dnssales Server

Example 13-11 Example Boot File for dnssecond Server

Example resolv.conf Files

Example 13-12 Example resolve.conf File for dnsmastr Server

Example 13-13 Example resolve.conf File for dnssales Server

Example 13-14 Example resolve.conf File for dnssecond Server

Example named.local File

Example 13-15 Example named.local File for Both Primary Servers

Example hosts Files

Example 13-16 Example db.doc File for dnsmastr server

Example 13-17 Example db.sales File for dnssales server

Example hosts.rev Files

Example 13-18 Example doc.rev File for dnsmastr server

Example 13-19 Example hosts.rev File for dnssales Server

Example name.ca File

Example 13-20 Example named.ca File

`$INCLUDE` Files

Setting Up the `resolv.conf` File

Example 13-1 Sample `resolv.conf` File for DNS Server

The `directory` Line

The `cache` Line

Setting Up the `named.ca` File

Internet `named.ca` File

Example 13-4 Example Internet `named.ca` file

Non-Internet `named.ca` File

Example 13-5 Sample `named.ca` File (Non-Internet)

Setting Up the `hosts` File

Example 13-6 Sample `hosts` File

Setting Up the `hosts.rev` File

Example 13-7 Sample `hosts.rev` File

Setting Up the `named.local` File

Example 13-8 Sample `named.local`File

Example 13-9 Example Boot File for `dnsmastr` Server

Example 13-10 Example Boot File for `dnssales` Server

Example 13-11 Example Boot File for `dnssecond` Server

Example `resolv.conf` Files

Example 13-12 Example `resolve.conf` File for `dnsmastr` Server

Example 13-13 Example `resolve.conf` File for `dnssales` Server

Example 13-14 Example `resolve.conf` File for `dnssecond` Server

Example `named.local` File

Example 13-15 Example `named.local` File for Both Primary Servers

Example `hosts` Files

Example 13-16 Example `db.doc` File for `dnsmastr` server

Example 13-17 Example `db.sales` File for `dnssales` server

Example `hosts.rev` Files

Example 13-18 Example `doc.rev` File for `dnsmastr` server

Example 13-19 Example `hosts.rev` File for `dnssales` Server

Example `name.ca` File

Example 13-20 Example `named.ca` File