This section shows the files you need to implement DNS for a sample Internet-connected network, based on the examples used in this chapter.
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.
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
The doc.com domain and zone is the top zone over the sales.doc.com subdomain and zone.
Each network has its own network number
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:
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 |
The following code examples show boot files for the three servers in the two networks:
; 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 |
; 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 |
; 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 |
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.)
; ; /etc/resolv.conf file for dnsmaster (sirius) ; domain doc.com nameserver 0.0.0.0 nameserver 111.22.3.5 |
; ; /etc/resolv.conf file for dnssales (altair) ; domain sales.doc.com nameserver 111.22.3.4 nameserver 123.45.6.1 |
; ; /etc/resolv.conf for dnssecond ; domain doc.com nameserver 111.22.3.5 nameserver 123.45.6.1 |
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.
; 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. |
The following code examples show db.doc and db.sales files for the two primary servers on the two networks.
; 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 |
; 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 |
The following code examples show hosts.rev files for the two primary servers on the two networks:
; 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. |
; 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 |
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.
; ; 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 |