How to Update the DNS Server Used by the BIND Resolver¶

The BIND resolver uses both a running configuration and a permanent configuration stored in TCP/IP Services. To replace a DNS server, the existing server must be removed from both configurations, the new server information added, and the resolver regenerated to activate the change. This procedure updates the DNS server used by the resolver and ensures the new configuration persists after a restart.

In this example OLD_DNS_SERVER (172.16.1.1) is replaced with NEW_DNS_SERVER (172.16.1.2).

Display the current running DNS server configuration.
```
$ TCPIP SHOW NAME_SERVICE
```
Review the output and note the server name. For example:
```
Servers:    OLD_DNS_SERVER
```

Remove the existing running DNS server entry.

$ TCPIP SET NAME_SERVICE /NOSERVER=OLD_DNS_SERVER/SYSTEM

Display the permanent DNS server configuration.
```
$ TCPIP SHOW CONFIGURATION NAME_SERVICE
```
Review the output and note the server name. For example:
```
Servers:    172.16.1.1
```

Remove the existing permanent DNS server entry.

$ TCPIP SET CONFIGURATION NAME /NOSERVER=172.16.1.1

Disable the resolver.

$ TCPIP SET NAME_SERVICE/DISABLE/SYSTEM

Remove the old host entry.

$ TCPIP SET NOHOST/NOCONFIRM 172.16.1.1

Add the new DNS Server host entry IP.

$ TCPIP SET HOST/ADDRESS=172.16.1.2 NEW_DNS_SERVER

Configure the new permanent DNS Server.

$ TCPIP SET CONFIGURATION NAME_SERVICE /SERVER=NEW_DNS_SERVER

Restart the BIND Resolver to apply the changes.
```
$ TCPIP GENERATE NAME_SERVICE
```
Verify that the new DNS server is active.
```
$ TCPIP SHOW NAME_SERVICE
```