Today I finally make my Linux Box works after weeks of effort. It took my quite a while to realise that the problem I had all along was my 3Com (3c905c-TX) doing. Even though I tested this card on other Microsoft machine and it works like a charm but on my Linux, It's been giving me one hell of time.
Long Story cut short, it seems that my 3Com (eth0) card has compatibility issue with RHL 9.0. Either if you put in a 2nd 3Com card or other brand (in my case Realtek), then the 3Com would generate error especially pinging. I was able to ping myself and I also double check my configuration, it is all alright. But not to the outside. So next time, any of you using 3Com NIC, beware of this issue.
and I would like to express my gratitude to you, Ricky, for your advices and support. Man, you rock!