[CentOS] Delay in SSH login..

Hi, I have CentOS 4.3 running on my AMD Athlon XP(32 bit) PC and Windows 2000 running on my other Intel P3 PC(These 2 PCs are connected using a network switch). Basically I use the one running Linux as back end server and everything was fine so far. But recently I am experiencing some delay in loggin in to CentOS through SSH.

The Putty client which I use generally opens up asking for username prompt(no delay in that) but after entering the password it takes atleast 10-15 seconds gap before I logged in. It was fine before and I am sure I didn't made any changes to linux configuration. Can anyone please help me with this issue.

By the way I always use the IP address like($ ssh user@192.168.0.xxx without any hostname)

thanks Lin