Technical data

Configuring and Managing BIND
5.7 Configuring the BIND Resolver
Assuming that the default domain is ucx.ern.sea.com , the resolver performs
lookups as follows:
1. On the host name and domain owl.ucx.ern.sea.com .
2. If that lookup was unsuccessful, the resolver searches for host owl .
This behavior is different than the resolver lookup behavior in previous releases
(UCX BIND Version 4.x.). The following section provides more information.
5.7.4 Resolver Search Behavior in Earlier Releases
In previous releases, the resolver performed lookups as follows:
1. Appended the default domain to the host name and performed a lookup.
2. If the previous lookup failed, the resolver removed the leftmost label from the
default domain name, appended the result to the host name and performed
the lookup.
3. If that lookup failed, the resolver again removed the leftmost label from the
default domain name, appended the result to the host name, and performed
the lookup.
For each unsuccessful lookup, this procedure was repeated until only two labels
remained in the resulting domain name.
If all these attempts failed, the resolver tried just the host name as typed (as long
as it contained at least one dot).
For example, suppose you entered the command:
TCPIP> SHOW HOST OWL
Assuming the default domain was ucx.ern.sea.com , the resolver performed
lookups as follows:
1. On owl.ucx.ern.sea.com .
2. If the previous lookup was unsuccessful, the resolver searched for
owl.ern.sea.com .
3. If that lookup was unsuccessful, the resolver searched for owl.sea.com .
4. Finally, if the preceding lookup was unsuccessful, the resolver searched for
owl .
5.7.5 Setting the Resolver’s Domain Search List
The search list is provided to make entering lookup commands easier by not
requiring you to type fully qualified domain names. The search list consists of
domain names that the resolver uses when performing lookups. By default,
the search list consists of only the default domain, which is stored in the
TCPIP$CONFIGURATION.DAT file.
You can change the elements in the search list by entering the
SET NAME_SERVICE command, as shown in the following example:
TCPIP> SET NAME_SERVICE /PATH=(ucx.ern.sea.com,dux.sea.com,mux.ern.sea.com)/SYSTEM
For example, if you enter the command:
TCPIP> SHOW HOST CANARY
The resolver performs lookups in the following sequence:
1. On canary.ucx.ern.sea.com .
Configuring and Managing BIND 5–35