Installing and Administering Internet Services

Chapter 3 105
Configuring and Administering the BIND Name Service
Troubleshooting the BIND Name Server
May fail to look up the local host’s name on startup and give a
servfail message. To check root server information, execute the
following:
$ nslookup
> set type=NS
> .
This asks for the NS records for the root. If no records for root
servers are present, it returns Can't find "." : Server
failed.
• ping hostname
Names in the local domain are found, while names in remote
domains are not found.
• Name server debugging output
Set debugging to level 1. ping a host name not in the local
domain. The debugging output in /var/tmp/named.run contains
the following: No root name servers for class 1. (Class 1 is
the IN class.)
• Dumping the name server database
No root server data appears in the “Hints” section at the end of the
file /var/tmp/named_dump.db.
4. Syntax errors in /etc/resolv.conf (for remote server
configuration only). This assumes that the server on the remote host
is configured properly. Errors in /etc/resolv.conf are silently
ignored by the resolver code.
• ping IP_address or ping hostname
Only names in the NIS or NIS+ database or /etc/hosts file can
be looked up. ping the remote server’s address to verify
connectivity.
• Name server debugging output
Turn on debugging on the remote server. Check that it is receiving
queries from the local host. If queries are not being received, check
the name server entries in /etc/resolv.conf and check
network connectivity to the remote server.
5. Network connectivity problems may cause certain lookups to fail. See
the Installing and Administering LAN/9000 Software manual for
information on troubleshooting network connectivity.