Troubleshooting Tools

When problems arise with DAS servers, clients, or connectivity, there are a number of tools available to help you out. You can use the following list as a guide:

• Verify IP connectivity
• Verify DNS resolution, DNS records, hostnames, and /etc/hosts entries
• Check firewalls and packetfilters, disable temporarily if necessary
• Make sure daemons are running and the appropriate ports are listening
• Check time synchronization
• Check logs on server or client
• Use a protocol analyzer (sniffer) like Ethereal to watch the network traffic
• Check your /etc/pam.d/ config files. These are especially error-prone.
• Use built-in diagnostic commands for Kerberos, NIS, RPC, and NTP.
• Sometimes shutting down NSCD on clients will help you isolate problems

Of course, make sure you have good config file backups before you start any intensive troubleshooting!

Final Question: Do you have a good network diagram? If not, why not?