I just recently upgraded my kernel from 2.2.13 to 2.3.99. As a result of the upgrade, I had to install IPFilter and libpcap. This particular machine has been serving as a masquerade gateway for a small network for a while now, with a caching DNS server, using ipchains, etc.
Now that I've upgraded my kernel, my network barely works. Dialing up to my ISP and using internet programs on the server works like a charm. Low to zero error rates, good transfer rates, everything is great.
I don't know if the cause is the new kernel or one of the other programs I installed, because I installed all of that stuff all at the same time.
My LAN is a different story. None of my standard services really work. I can't use FTP. Telnet sometimes works after many attempts, and when it does, I have to wait a long time to get a login: prompt.
Ping seems to drop the first 20-30 packets, then I receive duplicates and a whole slough of "1.5 ms" responses with a few "1003.4 ms" responses thrown in.
I have an Intel EtherExpress Pro 100 adapter, and I'm using the eepro100 driver. I have tried it both as a module and compiled in, and that makes no difference.
I don't know enough about ARP to know if this is useful information or not, but if I keep an eye on "arp -n" while I'm trying to ping, under "HW Address" it keeps saying "unresolved address" while it's dropping packets, and then the proper hardware address appears after 20-30 packets have been sent out, and I start getting responses.
I've been eyeballing the logs, but outside of the network programs I'm using timing out, I don't see anything unusual.
I wish I knew more about this so I knew what information I should provide. If anyone could even help me find out where to look, I would really appreciate it.