Installing and Administering Internet Services

Chapter 3 145
Configuring and Administering the BIND Name Service
Troubleshooting the BIND Name Server
• ping hostname
hostname is found only when it is a completely specified domain
name (with or without a trailing dot).
9. The /etc/nsswitch.conf file, if it exists, is not configured correctly.
If you want to query BIND before querying NIS or NIS+ or the
/etc/hosts file, make sure dns is listed first on the hosts line. See
“Configuring the Name Service Switch” on page 30.
10.The /etc/hosts file, NIS, or NIS+ contains incorrect data. The name
service switch (/etc/nsswitch.conf) allows host name lookups in
/etc/hosts, NIS, or NIS+ and one of those databases contains
incorrect data. For information on configuring the /etc/hosts file,
see “To Edit the /etc/hosts File” on page 35. For information on NIS
and NIS+, see Installing and Administering NFS Services.
Understanding Name Server Debugging Output
To diagnose problems in the debugging output of the name server, you
need to know what output from a successful query looks like. The
following two examples show output from successful host name lookups.
The first example does not involve any retransmissions, while the second
example does. Note that debugging output looks the same whether it
comes from a primary, secondary, or caching-only server.
Example 1: No Retransmissions
Debug turned ON, Level 1
datagram from 15.19.10.14 port 4258, fd 6, len 35
req: nlookup(john.dept.inc.com) id 1 type=1
req: found ’john.dept.inc.com’ as ’inc.com’ (cname=0)
forw: forw -> 192.67.67.53 6 (53) nsid=29 id=1 0ms retry 4 sec
datagram from 192.67.67.53 port 53, fd 6, len 166
resp: nlookup(john.dept.inc.com) type=1
resp: found ’john.dept.inc.com’ as ’inc.com’ (cname=0)
resp: forw -> 15.19.11.2 6 (53) nsid=32 id=1 0ms
datagram from 15.19.11.2 port 53, fd 6, len 119
resp: nlookup(john.dept.inc.com) type=1
resp: found ’john.dept.inc.com’ as ’dept.inc.com’ (cname=0)
resp: forw -> 15.19.15.15 6 (53) nsid=33 id=1 0ms