UNIX for Advanced & Expert Users

Sorry to say this, but this is a VERY BAD advice.

First off, there is a reason for using DNS instead of local host lists and it is maintainability. Everything you write into /etc/hosts you will have to change when the network changes. Chances are if this happens you forget to change one of the hundreds of hosts in one of the hundreds of /etc/hosts files and you are in for all sorts of trouble.

Second, doing this is curing the symptom - the slow response - but not the root of the problem - the slow name server. It would be equally justified to say: switch off the system and your response time will drop to zero.

If i have anything learned at all in the 30 years of practicing the obscure art of handling computers it is this: if you solve a problem then do it in the most thorough way possible and accept no compromise! It is likely that a problem "solved" in any other way will come back haunting you when you least expect it and/or when it is the most unpleasant time to that happening.

@Thread-O/P: start monitoring the system (after, like stated above, making sure no hardware malfunction is the culprit) to find out in which way the system is slow: usual problems (and hence good starting points for investigation) are: memory, processor, network I/O, disk I/O.

Do a vmstat to find out about memory/processor issues and netstat to find out about network I/O. Use iostat to get disk I/O statistics. If you don't know how to interpret the output of these tools report them back here, someone will be willing to do that for you.

I hope this helps.

bakunin

That was no offence sir..!! This would have been helpful if this node is making multiple connections with few IPs on different ports

No offense taken at all! If i have come across this way I'd like to apologize. This is an exchange of professional views on profession-related problems and it is quite expectable to be of differing opinions at one time or another.

I have learned much here from being corrected by others when i gave some less-than-sterling explanation and probably taught others the same way when i knew something better than they did. That's the way we all get better over time. And, btw., some contributors here are really, really good already. ;-))

On another thought, regarding the thread-O/Ps problem: have you checked the reverse-lookup tables on the name server? Maybe they are somehow not accessible as well as the lookup tables are?

I hope this helps.

bakunin

Still define you local server address in /etc/hosts. And anything which appears in netstat -r (including the default gateway) plus the DNS server itself. This will speed thing up no end. The biggest performance improvement is making a /etc/hosts entry for the DNS server itself.
It is a huge mistake to not have a /etc/hosts entry for your DNS server.