Slow DNS Lookups
 

Running CentOS 4.4. Whenever I go to a web URL or do any network activity outside of the LAN the lookup is extremely slow on the server. It takes from 3 - 10 seconds. Once it looks up though the speed is good, for example I can download files at 150KB a second. At first I though it was my firewall/router, but none of the other computers are experiencing this problem. I looked at the internal firewall built into CentOS and as I confirmed it is disabled, also Linux Enhanced Security is also disabled. Does any body have a clue what is going on? This didn’t use to happen.

This happens not only for HTTP traffic. For example, when I remote SSH into the sever it pops up the username and password field instantly, but it takes 5 - 10 seconds to authentic and show the prompt. This didn’t use to be the case, it used to authentic almost instantly.

Thanks for any help, comments.

Once it looks up though the speed is good, for example I can download files at 150KB a second.
No, it's good because the DNS query got cached, download speed is no measure for that.


This didn’t use to be the case, it used to authentic almost instantly.
Maybe try to get a fix on the time it started appearing and check what got changed/updated around that time?