Here's my network setup. DSL to router, router to linux box running
RH 7, serving as firewall. Mixed windows and linux network behind the
firewall. firewall is ipchains.
Late this afternoon, for no apparent reason, machines behind the
firewall can't access the web. I can ping the internet and I can run
a windows news client behind the firewall with no problem. Only thing
not going through seems to be www.
Here's where it's weird. There is one web site I can reach from
behind the firewall. Charles Schwab. I don't know if this is because
it's a "secure" site or not.
I'm not a network guru and I don't have a clue where to start. I run
tcpdump on the firewall and it looks like www traffic is not going
through because of some error in routing. I see messages about udp
error host or port unreachable, tos 0xc0.
Web access has been fine for months and this just started on it's own
late in the afternoon. I can get other traffic past the firewall, not
web traffic, except the schwab site as mentioned. Any suggestions on
how to troubleshoot this problem would really be appreciated.