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Solaris DHCP Administration Guide

Chapter 5 Troubleshooting DHCP

This chapter provides information to help you solve problems you might encounter when you configure a DHCP server or client, or problems in using DHCP after configuration is complete.

The chapter includes the following information:

Troubleshooting DHCP Server Problems

The problems you might encounter when you configure the server fall into the following categories:

NIS+ Problems

If you decide to use NIS+ as the DHCP data store, problems you might encounter can be categorized as follows:

Cannot Select NIS+ as a Data Store

If you try to use NIS+ as your data store, you might find that DHCP Manager does not offer it as a choice for data store, or dhcpconfig returns a message saying NIS+ does not appear to be installed and running. This means that NIS+ has not been configured for this server, although NIS+ might be in use on the network. Before you can select NIS+ as a data store, the server system must be configured as an NIS+ client.

Before you set up the server as an NIS+ client, the domain must have already been configured and its master server must be running. The master server of the domain's tables should be populated, and the hosts table must have an entry for the new client system (the DHCP server system). “Configuring NIS+ Clients” in Solaris Naming Setup and Configuration Guide provides detailed information about configuring an NIS+ client.

NIS+ Not Adequately Configured

After you successfully use NIS+ with DHCP, you might encounter errors if changes are made to NIS+ and introduce configuration problems. Use the following table to help you determine the cause of configuration problems.

Table 5–1 NIS+ Configuration Problems

Possible Problem 

Gather Information 

Solution 

Root object does not exist in the NIS+ domain.  

Enter the following command:  

/usr/lib/nis/nisstat

This command displays statistics for the domain. If the root object does not exist, no statistics are returned.

Set up the NIS+ domain using the Solaris Naming Setup and Configuration Guide.

NIS+ is not used for passwd and publickey information.

Enter the following command to view the name service switch configuration file:  

cat /etc/nsswitch.conf

Check the passwd and publickey entries for the “nisplus” keyword.

Refer to the Solaris Naming Setup and Configuration Guide for information about configuring the name service switch.

The domain name is empty. 

Enter the following command:  

domainname

If the command lists an empty string, no domain name has been set for the domain. 

Use local files for your data store, or set up an NIS+ domain for your network. Refer to Solaris Naming Setup and Configuration Guide.

The NIS_COLD_START file does not exist.

Enter the following command on the server system to determine if the file exists:  

cat /var/nis/NIS_COLD_START

Use local files for your data store, or create an NIS+ client. Refer to Solaris Naming Setup and Configuration Guide.

NIS+ Access Problems

NIS+ access problems might cause error messages about incorrect DES credentials, or inadequate permissions to update NIS+ objects or tables. Use the following table to determine the cause of NIS+ errors you receive.

Table 5–2 NIS+ Access Problems

Possible Problem 

Gather Information 

Solution 

The DHCP server system does not have create access to the org_dir object in the NIS+ domain.

Enter the following command:  

nisls -ld org_dir

The access rights are listed in the form r---rmcdrmcdr---, where the permissions apply respectively to nobody, owner, group, and world. The owner of the object is listed next.

Use the nischmod command to change the permissions for org_dir.

For example, to add create access to the group, type the following command:  

nischmod g+c org_dir

 

Normally the org_dir directory object provides full (read, modify, create, and destroy) rights to both the owner and the group, while providing only read access to the world and nobody classes.

See the nischmod(1) man page for more information.
 

The DHCP server name must either be listed as the owner of the org_dir object, or be listed as a principal in the group, and that group must have create access. List the group with the command:

nisls -ldg org_dir

 

The DHCP server does not have access rights to create a table under the org_dir object.

Usually, this means the server system's principal name is not a member of the owning group for the org_dir object, or no owning group exists.

Enter this command to find the owning group name:  

niscat -o org_dir

Look for a line similar to  

Group : "admin.myco.com."

List the principal names in the group using the command:  

nisgrpadm -l groupname

Add the server system's name to the group using the nisgrpadm command.

For example, to add the server name pacific to the group admin.myco.com, type the following command:

nisgrpadm -a admin.myco.com pacific.myco.com

 

For example: 

nisgrpadm -l admin.myco.com

The server system's name should be listed as an explicit member of the group or included as an implicit member of the group. 

See the nisgrpadm(1) man page for more information.

The DHCP server does not have valid Data Encryption Standard (DES) credentials in the NIS+ cred table.

If this is the problem, an error message states that the user does not have DES credentials in the NIS+ name service. 

Use the nisaddcred command to add security credentials for the DHCP server system.

The following example shows how to add DES credentials for the system mercury in the domain Faxco.COM:
  

nisaddcred -p unix.mercury@Faxco.COM \ -P mercury.Faxco.COM. DES Faxco.COM.

  

The command prompts for the root password (which is required to generate an encrypted secret key).  

See the nisaddcred(1M) man page for more information.

IP Address Allocation Errors

When a client attempts to obtain or verify an IP address, you might see the problems in the following table logged to syslog or in server debug output.

Table 5–3 IP Address Allocation and Lease Problems

Error Message 

Explanation 

Solution 

There is no n.n.n.n dhcp-network table for DHCP client's network.

A client is requesting a specific IP address or seeking to extend a lease on its current IP address but the DHCP server cannot find the DHCP network table for that address.  

The DHCP network table might have been deleted mistakenly. You can recreate the network table by adding the network again using DHCP Manager or dhcpconfig.

ICMP ECHO reply to OFFER candidate: n.n.n.n, disabling

The IP address considered for offering to a DHCP client is already in use. This might occur if more than one DHCP server owns the address, or if an address was manually configured for a non-DHCP network client. 

Determine the proper ownership of the address and correct either the DHCP server database or the host's network configuration. 

ICMP ECHO reply to OFFER candidate: n.n.n.n. No corresponding dhcp network record.

The IP address considered for offering to a DHCP client does not have a record in a network table. This might occur if the IP address record is deleted from the DHCP network table after the address was selected but before the duplicate address check was completed. 

Use DHCP Manager or pntadm to view the DHCP network table, and if the IP address is missing, create it with DHCP Manager (choose Create from the Edit menu on the Address tab) or pntadm.

DHCP network record for n.n.n.n is unavailable, ignoring request.

The record for the requested IP address is not in the DHCP network table, so the server is dropping the request.  

Use DHCP Manager or pntadm to view the DHCP network table, and if the IP address is missing, create it with DHCP Manager (choose Create from the Edit menu on the Address tab) or pntadm.

n.n.n.n currently marked as unusable.

The requested IP address cannot be offered because it has been marked in the network table as unusable.  

You can use DHCP Manager or pntadm to make the address usable.

n.n.n.n was manually allocated. No dynamic address will be allocated.

The client's ID has been assigned a manually allocated address, and that address is marked as unusable. The server cannot allocate a different address to this client.  

You can use DHCP Manager or pntadm to make the address usable, or manually allocate a different address to the client.

Manual allocation (n.n.n.n, client ID has n other records. Should have 0.

The client that has the specified client ID has been manually assigned more than one IP address. There should be only one. The server selects the last manually assigned address it finds in the network table.  

Use DHCP Manager or pntadm to modify IP addresses to remove the additional manual allocations.

No more IP addresses on n.n.n.n network.

All IP addresses currently managed by DHCP on the specified network have been allocated.  

Use DHCP Manager or pntadm to create new IP addresses for this network.

Client: clientid lease on n.n.n.n expired.

The lease was not negotiable and timed out.  

Client should automatically restart the protocol to obtain a new lease. 

Offer expired for client: n.n.n.n

The server made an IP address offer to the client, but the client took too long to respond and the offer expired. 

The client should automatically issue another discover message. If this also times out, increase the cache offer timeout for the DHCP server. In DHCP Manager, choose Modify from the Service menu.  

Client: clientid REQUEST is missing requested IP option.

The client's request did not specify the offered IP address, so the DHCP server ignores the request. This might occur if the client is not compliant with the updated DHCP protocol, RFC 2131. 

Update client software. 

Client: clientid is trying to renew n.n.n.n, an IP address it has not leased.

The IP address recorded in the DHCP network table for this client does not match the IP address that the client specified in its renewal request. The DHCP server does not renew the lease. 

This problem occurs if you delete a client's record while the client is still using the IP address. 

Use DHCP Manager or pntadm to examine the network table, and correct if necessary. The client's ID should be bound to the specified IP address. If it is not, edit the address properties to add the client ID.

Client: clientid is trying to verify unrecorded address: n.n.n.n, ignored.

The specified client has not been registered in the DHCP network table with this address, so the request is ignored by this DHCP server.  

Another DHCP server on the network might have assigned this client the address.  

However, you might also have deleted the client's record while the client was still using the IP address. 

Use DHCP Manager or pntadm to examine the network table on this server and any other DHCP servers on the network and correct if necessary.

You can also do nothing and allow the lease to expire, after which the client will automatically request a new address lease. 

If you want the client to get a new lease immediately, restart the DHCP protocol on the client by typing the following commands: 

ifconfig interface dhcp release

ifconfig interface dhcp start

Troubleshooting DHCP Client Configuration Problems

The problems you might encounter with a DHCP client fall into the following categories:

Problems Communicating With DHCP Server

This section describes problems you might encounter as you add DHCP clients to the network.

After you enable the client software and reboot the system, the client tries to reach the DHCP server to obtain its network configuration. If the client fails to reach the server, you might see error messages such as: 


DHCP or BOOTP server not responding

Before you can determine the problem you must gather diagnostic information from both the client and the server and analyze the information. To gather information you can:

  1. Run the client in debug mode.

  2. Run the server in debug mode.

  3. Start snoop to monitor network traffic.

You can do these things separately or concurrently.

The information you gather can help you determine if the problem is with the client, server, or a relay agent, and then you can find a solution.

How to Run the DHCP Client in Debug Mode

If you have a client that is not a Solaris DHCP client, refer to the client's documentation for information about how to run the client in debug mode.

If you have a Solaris DHCP client, use the following steps.

  1. Become superuser on the client system.

  2. Type the following commands to kill the DHCP client daemon and restart it in debug mode: 


    # pkill -x dhcpagent
# /sbin/dhcpagent -d1 -f &
# ifconfig interface dhcp start

    When run in debug mode, the client daemon displays messages to your screen as it performs DHCP requests. See DHCP Client Debug Output for information about client debug output.

How to Run the DHCP Server in Debug Mode

  1. Become superuser on the server system.

  2. Type the following commands to kill the DHCP daemon and restart it in debug mode:


    # pkill -x in.dhcpd
# /usr/lib/inet/in.dhcpd -d -v

    You should also use any in.dhcpd command-line options that you normally use when you run the daemon. For example, if you run the daemon as a BOOTP relay agent, include the -r option with the in.dhcpd -d -v command.

    When run in debug mode, the daemon displays messages to your screen as it processes DHCP/BOOTP requests. See DHCP Server Debug Output for information about server debug output.

How to Use snoop to Monitor DHCP Network Traffic

  1. Become superuser on the DHCP server system.

  2. Start snoop to begin tracing network traffic across the server's network interface. 


    # /usr/sbin/snoop -d interface -o snoop-output-filename udp port 67 or udp port 68

    For example:

    # /usr/sbin/snoop -d le0 -o /tmp/snoop.output udp port 67 or udp port 68

    Note that snoop continues to monitor the interface until you stop it explicitly by pressing Control-C after you have the information you need.

  3. Boot the client system, or restart the dhcpagent on the client system.

    Restarting dhcpagent is described in How to Run the DHCP Client in Debug Mode.

  4. On the server system, use snoop to display the output file with the contents of network packets:


    # /usr/sbin/snoop -i snoop-output-filename -x0 -v

    For example:

    # /usr/sbin/snoop -i /tmp/snoop.output -x0 -v

The -d switch with the dhcpagent command puts the client in debug mode with level 1 verbosity, and the -f switch causes output to be sent to the console instead of to syslog. Replace interface in the ifconfig command line with the name of the network interface of the client (for example, le0).

See DHCP snoop Output for information about interpreting the output.

DHCP Client Debug Output

The following example shows normal debug output when a DHCP client sends its DHCP request and receives its configuration information from a DHCP server.

Example 5–1 Sample Normal DHCP Client Debug Output


/sbin/dhcpagent: debug: set_packet_filter: set filter 0x27fc8 (DHCP filter) 
/sbin/dhcpagent: debug: init_ifs: initted interface le0 
/sbin/dhcpagent: debug: insert_ifs: le0: sdumax 1500, optmax 1260, hwtype 1, hwlen 6 
/sbin/dhcpagent: debug: insert_ifs: inserted interface le0 
/sbin/dhcpagent: debug: register_acknak: registered acknak id 5 
/sbin/dhcpagent: debug: unregister_acknak: unregistered acknak id 5 
/sbin/dhcpagent: debug: set_packet_filter: set filter 0x26018 (ARP reply filter)
/sbin/dhcpagent: info: setting IP netmask on le0 to 255.255.192.0 
/sbin/dhcpagent: info: setting IP address on le0 to 102.23.3.233 
/sbin/dhcpagent: info: setting broadcast address on le0 to 102.23.63.255 
/sbin/dhcpagent: info: added default router 102.23.0.1 on le0 
/sbin/dhcpagent: debug: set_packet_filter: set filter 0x28054 (blackhole filter) 
/sbin/dhcpagent: debug: configure_if: bound ifsp->if_sock_ip_fd 
/sbin/dhcpagent: info: le0 acquired lease, expires Tue Aug 10 16:18:33 1999 
/sbin/dhcpagent: info: le0 begins renewal at Tue Aug 10 15:49:44 1999 
/sbin/dhcpagent: info: le0 begins rebinding at Tue Aug 10 16:11:03 1999

If the client cannot reach the DHCP server, you might see debug output similar to the following example.

Example 5–2 Sample Debug Output for DHCP Client


/sbin/dhcpagent: debug: set_packet_filter: set filter 0x27fc8 (DHCP filter)
/sbin/dhcpagent: debug: init_ifs: initted interface le0 
/sbin/dhcpagent: debug: select_best: no valid OFFER/BOOTP reply
/sbin/dhcpagent: debug: select_best: no valid OFFER/BOOTP reply
/sbin/dhcpagent: debug: select_best: no valid OFFER/BOOTP reply

If you see this message, the request never reached the server, or the server cannot send a response to the client. Run snoop on the server as described in How to Use snoop to Monitor DHCP Network Traffic to determine if packets from the client have reached the server.

DHCP Server Debug Output

Normal server debug output shows server configuration information followed by information about each network interface as the daemon starts. After daemon startup, the debug output shows information about requests the daemon processes. Example 5–3 shows debug output for a DHCP server that has just started and then extends the lease for a client that is using an address owned by another DHCP server that is not responding.

Example 5–3 Sample Debug Output for DHCP Server


Daemon Version: 3.1  
Maximum relay hops: 4  
Transaction logging to console enabled.  
Run mode is: DHCP Server Mode.  
Datastore: nisplus  
Path: org_dir.dhcp.test..:dhcp.test..:$ 
DHCP offer TTL: 10  
Ethers compatibility enabled.  
BOOTP compatibility enabled.  
ICMP validation timeout: 1000 milliseconds, Attempts: 2.  
Monitor (0005/hme0) started...  
Thread Id: 0005 - Monitoring Interface: hme0 *****  
MTU: 1500      Type: DLPI  
Broadcast: 102.21.255.255 
Netmask: 255.255.0.0  
Address: 102.21.0.2  
Monitor (0006/nf0) started...  
Thread Id: 0006 - Monitoring Interface: nf0 *****  
MTU: 4352      Type: DLPI  
Broadcast: 102.22.255.255  
Netmask: 255.255.0.0  
Address: 102.22.0.1  
Monitor (0007/qe0) started...  
Thread Id: 0007 - Monitoring Interface: qe0 *****  
MTU: 1500      Type: DLPI   
Broadcast: 102.23.63.255  
Netmask: 255.255.192.0  
Address: 102.23.0.1  
Read 33 entries from DHCP macro database on Tue Aug 10 15:10:27 1999 
Datagram received on network device: qe0  
Client: 0800201DBA3A is requesting verification of address owned by 102.21.0.4 
Datagram received on network device: qe0  
Client: 0800201DBA3A is requesting verification of address owned by 102.21.0.4  
Datagram received on network device: qe0  
Client: 0800201DBA3A is requesting verification of address owned by 102.21.0.4  
Datagram received on network device: qe0  
Client: 0800201DBA3A maps to IP: 102.23.3.233  
Unicasting datagram to 102.23.3.233 address.  
Adding ARP entry: 102.23.3.233 == 0800201DBA3A  
DHCP EXTEND 0934312543 0934316143 102.23.3.233 102.21.0.2 
          0800201DBA3A SUNW.SPARCstation-10 0800201DBA3A

Example 5–4 shows debug output from a DHCP daemon that starts as a BOOTP relay agent and relays requests from a client to a DHCP server, and relays the servers responses to the client.

Example 5–4 Sample Debug Output for BOOTP Relay


Relay destination: 102.21.0.4 (blue-servr2)     network: 102.21.0.0  
Daemon Version: 3.1  
Maximum relay hops: 4  
Transaction logging to console enabled.  
Run mode is: Relay Agent Mode.  
Monitor (0005/hme0) started...  
Thread Id: 0005 - Monitoring Interface: hme0 *****  
MTU: 1500      Type: DLPI  
Broadcast: 102.21.255.255  
Netmask: 255.255.0.0  
Address: 102.21.0.2  
Monitor (0006/nf0) started...  
Thread Id: 0006 - Monitoring Interface: nf0 *****  
MTU: 4352      Type: DLPI  
Broadcast: 102.22.255.255  
Netmask: 255.255.0.0  
Address: 102.22.0.1  
Monitor (0007/qe0) started...  
Thread Id: 0007 - Monitoring Interface: qe0 *****  
MTU: 1500      Type: DLPI  
Broadcast: 102.23.63.255  
Netmask: 255.255.192.0  
Address: 102.23.0.1  
Relaying request 0800201DBA3A to 102.21.0.4, server port.  
BOOTP RELAY-SRVR 0934297685 0000000000 0.0.0.0 102.21.0.4 0800201DBA3A 
N/A 0800201DBA3A  
Packet received from relay agent: 102.23.0.1  
Relaying reply to client 0800201DBA3A  
Unicasting datagram to 102.23.3.233 address.  
Adding ARP entry: 102.23.3.233 == 0800201DBA3A  
BOOTP RELAY-CLNT 0934297688 0000000000 102.23.0.1 102.23.3.233 0800201DBA3A 
N/A 0800201DBA3A  
Relaying request 0800201DBA3A to 102.21.0.4, server port.  
BOOTP RELAY-SRVR 0934297689 0000000000 0.0.0.0 102.21.0.4 0800201DBA3A 
N/A 0800201DBA3A  
Packet received from relay agent: 102.23.0.1  
Relaying reply to client 0800201DBA3A  
Unicasting datagram to 102.23.3.233 address.  
Adding ARP entry: 102.23.3.233 == 0800201DBA3A

If there is a problem, the debug output might display warnings or error messages. Use Table 5–4 to find error messages and solutions.

Table 5–4 DHCP Server Error Messages

Message 

Explanation 

Solution 

ICMP ECHO reply to OFFER candidate: ip_address disabling

Before the DHCP server offers an IP address to a client, it pings the address to verify that the address is not in use. If a client replies, the address is in use. 

Make sure the addresses you configured are not already in use. 

No more IP addresses on network_address network.

No available IP addresses in the DHCP network table associated with the client's network. 

Create more IP addresses using DHCP Manager or pntadm. If the DHCP daemon is monitoring multiple subnets, be sure the additional addresses are for the subnet where the client is located.

No more IP addresses for network_address network when you are running the DHCP daemon in BOOTP compatibility mode (-b option).

BOOTP does not use a lease time, so the DHCP server looks for free addresses with the BOOTP flag set to allocate to BOOTP clients. 

Use DHCP Manager to allocate BOOTP addresses. 

Request to access nonexistent per network database: database_name in datastore: datastore.

During configuration of the DHCP server, a DHCP network table for a subnet was not created.  

Use DHCP Manager or the pntadm to create the DHCP network table and new IP addresses.

There is no table_name dhcp-network table for DHCP client's network.

During configuration of the DHCP server, a DHCP network table for a subnet was not created.  

Use DHCP Manager or the pntadm to create the DHCP network table and new IP addresses.

Client using non_RFC1048 BOOTP cookie.

A device on the network is trying to access an unsupported implementation of BOOTP. 

Ignore this message, unless you need to configure this device. 

DHCP snoop Output

In the snoop output, you should see that packets are exchanged between the DHCP client system and the DHCP server system. The IP address for each system (and any relay agents or routers in between) is indicated in each packet. If the systems do not exchange packets, the client system might not be able to contact the server system at all, and the problem is at a lower level.

To evaluate snoop output, you should know what the expected behavior is (such as if the request should be going through a BOOTP relay agent). You should also know the MAC addresses and IP address of the systems involved (and those of the network interfaces, if there is more than one) so that you can determine if those values are as expected. The following example shows normal snoop output for a DHCP acknowledgement message sent from the DHCP server on blue-servr2 to a client whose MAC address is 8:0:20:8e:f3:7e. In the message, the servers assigns the client the IP address 172.168.252.6 and the host name white-6. The message also includes a number of standard network options and several vendor-specific options for the client.

Example 5–5 Sample snoop Output for One Packet


ETHER:  ----- Ether Header ----- 
ETHER:   
ETHER:  Packet 26 arrived at 14:43:19.14 
ETHER:  Packet size = 540 bytes 
ETHER:  Destination = 8:0:20:8e:f3:7e, Sun 
ETHER:  Source      = 8:0:20:1e:31:c1, Sun 
ETHER:  Ethertype = 0800 (IP) 
ETHER:  
IP:   ----- IP Header ----- 
IP:    
IP:   Version = 4 
IP:   Header length = 20 bytes 
IP:   Type of service = 0x00 
IP:         xxx. .... = 0 (precedence) 
IP:         ...0 .... = normal delay 
IP:         .... 0... = normal throughput 
IP:         .... .0.. = normal reliability 
IP:   Total length = 526 bytes 
IP:   Identification = 64667 
IP:   Flags = 0x4 IP:         .1.. .... = do not fragment 
IP:         ..0. .... = last fragment 
IP:   Fragment offset = 0 bytes 
IP:   Time to live = 254 seconds/hops 
IP:   Protocol = 17 (UDP) 
IP:   Header checksum = 157a 
IP:   Source address = 102.21.0.4, blue-servr2 
IP:   Destination address = 192.168.252.6, white-6 
IP:   No options 
IP:   UDP:  ----- UDP Header ----- 
UDP:   
UDP:  Source port = 67 
UDP:  Destination port = 68 (BOOTPC) 
UDP:  Length = 506  
UDP:  Checksum = 5D4C  
UDP:  
DHCP: ----- Dynamic Host Configuration Protocol ----- 
DHCP:  
DHCP: Hardware address type (htype) =  1 (Ethernet (10Mb)) 
DHCP: Hardware address length (hlen) = 6 octets 
DHCP: Relay agent hops = 0 
DHCP: Transaction ID = 0x2e210f17 
DHCP: Time since boot = 0 seconds 
DHCP: Flags = 0x0000 
DHCP: Client address (ciaddr) = 0.0.0.0 
DHCP: Your client address (yiaddr) = 172.168.252.6 
DHCP: Next server address (siaddr) = 102.21.0.2 
DHCP: Relay agent address (giaddr) = 0.0.0.0 
DHCP: Client hardware address (chaddr) = 08:00:20:11:E0:1B 
DHCP:  
DHCP: ----- (Options) field options ----- 
DHCP:  
DHCP: Message type = DHCPACK 
DHCP: DHCP Server Identifier = 102.21.0.4 
DHCP: Subnet Mask = 255.255.255.0 
DHCP: Router at = 172.168.252.1 
DHCP: Broadcast Address = 172.168.252.255 
DHCP: NISPLUS Domainname = dhcp.test 
DHCP: IP Address Lease Time = 3600 seconds 
DHCP: UTC Time Offset = -14400 seconds 
DHCP: RFC868 Time Servers at = 102.21.0.4 
DHCP: DNS Domain Name = sem.west.dor.com 
DHCP: DNS Servers at = 102.21.0.1 
DHCP: Client Hostname = white-6 
DHCP: Vendor-specific Options (166 total octets): 
DHCP:   (02) 04 octets  0x8194AE1B (unprintable) 
DHCP:   (03) 08 octets  "pacific" 
DHCP:   (10) 04 octets  0x8194AE1B (unprintable) 
DHCP:   (11) 08 octets  "pacific" 
DHCP:   (15) 05 octets  "xterm" 
DHCP:   (04) 53 octets  "/export/s28/base.s28s_nxt/latest/Solaris_8/Tools/Boot" 
DHCP:   (12) 32 octets  "/export/s28/base.s28s_nxt/latest" 
DHCP:   (07) 27 octets  "/platform/sun4m/kernel/unix" 
DHCP:   (08) 07 octets  "EST5EDT" 
  0: 0800 208e f37e 0800 201e 31c1 0800 4500    .. .ó~.. .1...E.
 16: 020e fc9b 4000 fe11 157a ac15 0004 c0a8    ....@....z......           
 32: fc06 0043 0044 01fa 5d4c 0201 0600 2e21    ...C.D..]L.....!           
 48: 0f17 0000 0000 0000 0000 c0a8 fc06 ac15    ................           
 64: 0002 0000 0000 0800 2011 e01b 0000 0000    ........ .......           
 80: 0000 0000 0000 0000 0000 0000 0000 0000    ................           
 96: 0000 0000 0000 0000 0000 0000 0000 0000    ................          
112: 0000 0000 0000 0000 0000 0000 0000 0000    ................          
128: 0000 0000 0000 0000 0000 0000 0000 0000    ................          
144: 0000 0000 0000 0000 0000 0000 0000 0000    ................          
160: 0000 0000 0000 0000 0000 0000 0000 0000    ................          
176: 0000 0000 0000 0000 0000 0000 0000 0000    ................          
192: 0000 0000 0000 0000 0000 0000 0000 0000    ................          
208: 0000 0000 0000 0000 0000 0000 0000 0000    ................          
224: 0000 0000 0000 0000 0000 0000 0000 0000    ................          
240: 0000 0000 0000 0000 0000 0000 0000 0000    ................          
256: 0000 0000 0000 0000 0000 0000 0000 0000    ................          
272: 0000 0000 0000 6382 5363 3501 0536 04ac    ......c.Sc5..6..          
288: 1500 0401 04ff ffff 0003 04c0 a8fc 011c    ................          
304: 04c0 a8fc ff40 0964 6863 702e 7465 7374    .....@.dhcp.test          
320: 3304 0000 0e10 0204 ffff c7c0 0404 ac15    3...............          
336: 0004 0f10 736e 742e 6561 7374 2e73 756e    ....sem.west.dor          
352: 2e63 6f6d 0604 ac15 0001 0c07 7768 6974    .com........whit          
368: 652d 362b a602 0481 94ae 1b03 0861 746c    e-6+.........pac          
384: 616e 7469 630a 0481 94ae 1b0b 0861 746c    ific.........pac          
400: 616e 7469 630f 0578 7465 726d 0435 2f65    ific...xterm.5/e          
416: 7870 6f72 742f 7332 382f 6261 7365 2e73    xport/s28/bcvf.s          
432: 3238 735f 776f 732f 6c61 7465 7374 2f53    28s_btf/latest/S          
448: 6f6c 6172 6973 5f38 2f54 6f6f 6c73 2f42    olaris_x/Tools/B          
464: 6f6f 740c 202f 6578 706f 7274 2f73 3238    oot. /export/s28          
480: 2f62 6173 652e 7332 3873 5f77 6f73 2f6c    /bcvf.s28s_btf/l         
496: 6174 6573 7407 1b2f 706c 6174 666f 726d    atest../platform          
512: 2f73 756e 346d 2f6b 6572 6e65 6c2f 756e    /sun4m/kernel/un          
528: 6978 0807 4553 5435 4544 54ff              ix..EST5EDT.

Problems with Inaccurate DHCP Configuration Information

If a DHCP client receives inaccurate information in its network configuration information, such as the wrong NIS domain name, or incorrect router IP address, you must look at the values of options in the macros that are processed by the DHCP server for this client.

Use the following general guidelines to help you determine the source of the inaccurate information.

Problems with Client-Supplied Host Name

This section describes problems you might experience with DHCP clients that supply their own host names and want the names to be registered with DNS.

Client Does Not Request a Host Name

If your client is not a Solaris DHCP client, consult the client's documentation to determine how to configure the client to request a host name. For Solaris DHCP clients, see How to Enable a Solaris Client to Request Specific Host Name.

DHCP Client Does Not Get Requested Host Name

Table 5–5 Problems and Solutions for DHCP Client Host Name Requests

Possible problem 

Gather Information 

Solution 

Client accepted an offer from a DHCP server that does not issue DNS updates. 

  1. Use snoop or other network packet capture application on the client. Look for the DHCP Server Identifier to get the IP address of the server.

  2. Log in to the DHCP server to verify that it is configured to make dynamic updates. Look at the /etc/inet/dhcpsvc.conf file for the entry UPDATE_TIMEOUT.

  3. On the DNS server, look at the /etc/named.conf file and determine if the DHCP server's IP address is listed in the allow-update keyword in the zone section of the appropriate domain.

See Enabling Dynamic DNS Updates by DHCP Server for information about configuring the DHCP server and DNS server.

If two DHCP servers are available to the client, the servers should both be configured to provide the DNS updates. 

Client is using FQDN option (option code 89) to specify host name. Solaris DHCP does not currently support FQDN option since it not officially in the DHCP protocol. 

Use snoop or other network packet capture application on the server, and look for the FQDN option in a packet from client.

Configure the client to specify host name using Hostname option (option code 12). Refer to client documentation for instructions.

DHCP server that offers the client its address does not know the client's DNS domain. 

On the DHCP server look for the DNSdmain option with a valid value.

Set the DNSdmain option to the correct DNS domain name in a macro that is processed for this client. DNSdmain is usually contained in the network macro.

Host name requested by client corresponds to an IP address that is not managed by the DHCP server. Solaris DHCP servers do not perform DNS updates for IP addresses they do not manage. 

Check syslog for messages from the DHCP server similar to There is no n.n.n.n dhcp-network table for DHCP client's network. or DHCP network record for n.n.n.n is unavailable, ignoring request.

Configure the client to choose a name for which there is no corresponding IP address, or which corresponds to an address managed by the DHCP server. 

Host name requested by client corresponds to an IP address that is currently in use, leased, or under offer to another client. 

Check syslog for messages from the DHCP server indicating ICMP ECHO reply to OFFER candidate: n.n.n.n.

Configure the client to choose a name corresponding to a different IP address. Alternatively, reclaim the address from the client that uses the address.  

DNS server is not configured to accept updates from the DHCP server. 

Examine the /etc/named.conf file on the DNS server and look for the DHCP server's IP address with the allow-update keyword in the appropriate zone section for the DHCP server's domain.

See How to Enable Dynamic DNS Updating for DHCP Clients for information about configuring the DNS server.

If the DHCP server has multiple interfaces, you may need to configure the DNS server to accept updates from all of the DHCP server's addresses. Enable debugging on the DNS server to see whether the updates are reaching the DNS server; if they are, examine the debugging output to determine why the updates did not occur. 

DNS updates may not have completed in the allotted time. DHCP servers do not return host names to clients if the DNS updates have not completed by the configured time limit. However, attempts to complete the DNS updates continue. 

Use the nslookup command to determine whether the updates completed successfully. See nslookup(1M) man page.

For example, if the DNS domain is hills.oneonta.org, the DNS server's IP address is 121.76.178.11, and the host name the client wants to register is cathedral, you could use the following command to determine if cathedral has been registered with DNS:

nslookup cathedral.hills.oneonta.org 121.76.178.11

If the updates completed successfully, but not in the allotted time, you need to increase the timeout value. See Step 5 in the procedure for enabling DNS updates.