Don't be alarm, I found this problem, however if you are interesting to know,

I accidentally installed this tcpip-0.17-i486-38.tgz from current-tree over tcpip-0.17-i486-35.tgz, this is the original package from 10.2. And, I had problem with my DNS server for days. It compeltely block DNS request and answers, however it didn't show up in the log file, everything looked normal, and routing tables are fine; so you still can go to website if you know these ip numbers, anyway, it just would not allow the dns to forward query to another server, or these dns answers were completely ignored.

And all other packages was alreday updated with paches from 10.2. Once, I had put back this original package; everything works again.

Lessons learnt: never mix the core packages from two different Slackware releases. The tcpip package is actually a union of a lot of packages. They are quite tied to the Slackware release they're part of.

Eric