Server slow on authentication process

Hi, I have installed SLES 8. It’s my mail server. After some time, the authentication process and some commands, like useradd, are very slow. I did a lot of test and perceived that when I stopped the network service, the time to execute the commands return to normal, so I reinstalled the iproute2 and sysconfig packets. This action solved my problem, but after some days the problem happened again. I tried reinstalling the iproute2 packet, but the problem was not solved this time. Any idea? Thanks, Julio Cesar Reitor PS: Sorry my bad English. --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.782 / Virus Database: 528 - Release Date: 10/22/2004