Installing and Administering Internet Services

106 Chapter 3
Configuring and Administering the BIND Name Service
Troubleshooting the BIND Name Server
• Name server debugging output
Turn on debug level 1. ping the host name. Check the name
server debugging output in /var/tmp/named.run for lines like
this:
req: found 'cucard.med.columbia.edu' as 'columbia.edu'
resend(addr=1 n=0) -> 128.59.32.1 6 (53) nsid=18 id=1 0ms
resend(addr=2 n=0) -> 128.59.40.130 6 (53) nsid=18 id=1 0ms
resend(addr=3 n=0) -> 128.103.1.1 6 (53) nsid=18 id=1 764ms
In this case the name server is trying to contact the
columbia.edu name servers but is not getting a response. Check
network connectivity by pinging the addresses the server is
trying to contact.
If the addresses being tried are the root name servers, either the
host does not have connectivity to these machines, or the root
server addresses are wrong.
• nslookup
nslookup times out while trying to look up the name.
• ping hostname
A message is returned saying that the host is unknown.
6. Secondary master is unable to load from another master. This may be
caused by a configuration error or problems with network
connectivity. Check that the domain being loaded and the address of
the remote server are correct in the boot file.
• syslogd
An error message is logged indicating the master server for the
secondary zone is unreachable.
• Name Server debugging output
Start the secondary server at debugging level 2 or 3. Watch for
error messages in the debug output. These could show that the
other server is unreachable, the other server is not authoritative
for the domain, or the local SOA serial number is higher than the
remote SOA serial number for this zone.
• ping IP_address
Verify connectivity to the server the secondary is trying to load
from. If the host is temporarily unreachable, the secondary server
will load when it is reachable.