After the configuration of the domain name system (DNS) server is completed in a new site, the status of the DNS server can be checked by running DSP DNS on the local maintenance terminal (LMT) of the serving GPRS support node (SGSN). A sample output of the command is as follows:

 IP address          Priority   DNS Server name   Status     Recursion available  221.177.202.41       1           master            Faulty     Yes  221.177.202.45       2           slave             Faulty     Yes  (Number of results = 2)

The output of the command indicates that DNS services are abnormal.

Possible Causes

• The link between the SGSN and the DNS server fails.
• The configuration of the DNS server is incorrect.
  

Procedure

1. Run ping to check whether SGSN UGTPs can be pinged from Master and Slave DNS servers and whether Master and Slave DNS servers can be pinged from SGSN UGTPs.

   If the ping is successful, the communication link between the SGSN and the DNS server is normal.

2. Check the log information in the messages file in /usr/adm/.

   Nov 17 15:14:58 GYDNS03BHW.GZ.MNC000.MCC460.GPRS named[307]: [ID 873579 daemon.notice] starting BIND 9.5.1-P3 Nov 17 15:14:58 GYDNS03BHW.GZ.MNC000.MCC460.GPRS named[307]: [ID 873579 daemon.error] /etc/named.conf:62: option also-notify is not allowed          in hint zone . Nov 17 15:14:58 GYDNS03BHW.GZ.MNC000.MCC460.GPRS named[307]: [ID 873579 daemon.crit] loading configuration: failure Nov 17 15:14:58 GYDNS03BHW.GZ.MNC000.MCC460.GPRS named[307]: [ID 873579 daemon.crit] exiting (due to fatal error) Nov 17 15:14:58 GYDNS03BHW.GZ.MNC000.MCC460.GPRS svc.startd[7]: [ID 652011 daemon.warning] svc:/network/dns/server:default: Method "/lib/svc/        method/dns-server start default" failed with exit status 1.

   The second message includes "/etc/named.conf:62: option also-notify is not allowed in hint zone ." This message indicates that the "hint" zone in the named.conf file cannot be configured with syntax "also-notify". The system fails to load the configuration file because the named.conf file is incorrectly configured. As a result, processes are forced to exit.

3. Delete the "also-notify" option of the "hint" zone from the named.conf file of Master and Slave DNS servers.
4. Restart the DNS server and the SGSN resolution becomes normal.

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What is the difference between caching DNS & Regular DNS?

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