Chapter 11 Troubleshooting DHCP (Reference)
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
-
NIS+ is not adequately configured
-
NIS+ access problems due to insufficient permissions and credentials
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). “Setting Up NIS+ Client Machines” in System Administration Guide: Naming and Directory Services
(FNS and NIS+) 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 11–1 NIS+ Configuration Problems
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 11–2 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.example.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.example.com, type the following command:
nisgrpadm -a
admin.example.com pacific.example.com
|
| |
For example:
nisgrpadm -l
admin.example.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 example.com:
|
| | |
nisaddcred -p unix.mercury@example.com
\ -P mercury.example.com. DES example.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 11–3 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:
-
Run the client in debug mode.
-
Run the server in debug mode.
-
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.
-
Become superuser on the client system.
-
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
-
Become superuser on the server system.
-
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
-
Become superuser on the DHCP
server system.
-
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.
-
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.
-
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 11–1 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 10.23.3.233
/sbin/dhcpagent: info: setting broadcast address on le0 to 10.23.63.255
/sbin/dhcpagent: info: added default router 10.23.0.1 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 11–2 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 11–3 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 11–3 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: 10.21.255.255
Netmask: 255.255.0.0
Address: 10.21.0.2
Monitor (0006/nf0) started...
Thread Id: 0006 - Monitoring Interface: nf0 *****
MTU: 4352 Type: DLPI
Broadcast: 10.22.255.255
Netmask: 255.255.0.0
Address: 10.22.0.1
Monitor (0007/qe0) started...
Thread Id: 0007 - Monitoring Interface: qe0 *****
MTU: 1500 Type: DLPI
Broadcast: 10.23.63.255
Netmask: 255.255.192.0
Address: 10.23.0.1
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 10.21.0.4
Datagram received on network device: qe0
Client: 0800201DBA3A is requesting verification of address owned by 10.21.0.4
Datagram received on network device: qe0
Client: 0800201DBA3A is requesting verification of address owned by 10.21.0.4
Datagram received on network device: qe0
Client: 0800201DBA3A maps to IP: 10.23.3.233
Unicasting datagram to 10.23.3.233 address.
Adding ARP entry: 10.23.3.233 == 0800201DBA3A
DHCP EXTEND 0934312543 0934316143 10.23.3.233 10.21.0.2
0800201DBA3A SUNW.SPARCstation-10 0800201DBA3A
|
Example 11–4 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 11–4 Sample Debug Output for BOOTP Relay
Relay destination: 10.21.0.4 (blue-servr2) network: 10.21.0.0
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: 10.21.255.255
Netmask: 255.255.0.0
Address: 10.21.0.2
Monitor (0006/nf0) started...
Thread Id: 0006 - Monitoring Interface: nf0 *****
MTU: 4352 Type: DLPI
Broadcast: 10.22.255.255
Netmask: 255.255.0.0
Address: 10.22.0.1
Monitor (0007/qe0) started...
Thread Id: 0007 - Monitoring Interface: qe0 *****
MTU: 1500 Type: DLPI
Broadcast: 10.23.63.255
Netmask: 255.255.192.0
Address: 10.23.0.1
Relaying request 0800201DBA3A to 10.21.0.4, server port.
BOOTP RELAY-SRVR 0934297685 0000000000 0.0.0.0 10.21.0.4 0800201DBA3A
N/A 0800201DBA3A
Packet received from relay agent: 10.23.0.1
Relaying reply to client 0800201DBA3A
Unicasting datagram to 10.23.3.233 address.
Adding ARP entry: 10.23.3.233 == 0800201DBA3A
BOOTP RELAY-CLNT 0934297688 0000000000 10.23.0.1 10.23.3.233 0800201DBA3A
N/A 0800201DBA3A
Relaying request 0800201DBA3A to 10.21.0.4, server port.
BOOTP RELAY-SRVR 0934297689 0000000000 0.0.0.0 10.21.0.4 0800201DBA3A
N/A 0800201DBA3A
Packet received from relay agent: 10.23.0.1
Relaying reply to client 0800201DBA3A
Unicasting datagram to 10.23.3.233 address.
Adding ARP entry: 10.23.3.233 == 0800201DBA3A
|
If there is a problem, the debug output might display warnings or error
messages. Use Table 11–4 to find error messages
and solutions.
Table 11–4 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 11–5 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 = 10.21.0.4, 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) = 192.168.252.6
DHCP: Next server address (siaddr) = 10.21.0.2
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 = 10.21.0.4
DHCP: Subnet Mask = 255.255.255.0
DHCP: Router at = 192.168.252.1
DHCP: Broadcast Address = 192.168.252.255
DHCP: NISPLUS Domainname = dhcp.test
DHCP: IP Address Lease Time = 3600 seconds
DHCP: UTC Time Offset = -14400 seconds
DHCP: RFC868 Time Servers at = 10.21.0.4
DHCP: DNS Domain Name = sem.example.com
DHCP: DNS Servers at = 10.21.0.1
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/s2/base.s2s/latest/Solaris_8/Tools/Boot"
DHCP: (12) 32 octets "/export/s2/base.s2s/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.example.
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/sx2/bcvf.s
432: 3238 735f 776f 732f 6c61 7465 7374 2f53 2xs_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/s2x
480: 2f62 6173 652e 7332 3873 5f77 6f73 2f6c /bcvf.s2xs_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 11–5 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.
|
-
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.
-
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.
-
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.example.org, the DNS server's IP address is 10.76.178.11, 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.example.org
10.76.178.11
|
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.
|
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