Verifying the DNS configuration

About verifying the DNS configuration

Troubleshoot the DNS configuration as you would on any network. The only difference is the location where the DNS values are configured on the NetCache appliance.

Determining whether a DNS problem prevents reaching a host

NetCache error messages distinguish between a problem with a connection (the connection or the host is down) and a failure when an attempt is made to translate the host name to an IP address. If you receive an error message that indicates the latter, it is likely that a DNS problem exists. A DNS problem might be limited to only some hosts or it might be global.

Network Appliance recommends that you confirm that NetCache is not causing the problem before you investigate a potential DNS problem. You can do so by using the ping command or nslookup from a non-NetCache computer to request name resolution for the host for which you are receiving error messages. If you experience the same problem, then the problem is on the server side. If the problem is gone, continue your NetCache troubleshooting by checking the DNS configuration items in the next section.

Configuration items to check for DNS

Check the following DNS items:

The nameservers and the appliance domain name
- In the Appliance Manager, this information is configured on the DNS - General page (Setup tab > DNS > General).
- In the NetCache CLI, use the show status.dns.* command.
The DNS configuration on your nameserver
Make sure that your nameserver is still able to service the DNS queries.

What else to check

While troubleshooting DNS configuration, also check the items in the following table.

If...	Then...
URLs outside the firewall cannot be accessed	Make sure that the DNS server that the NetCache appliance is configured with can resolve the Internet names (external URLs).
URLs inside the firewall cannot be accessed	Make sure that the DNS server is able to resolve the URLs that you are trying to access.