> Chad, > > It sounds like you've fallen prey to the perils of assymmetric > routing. For simplicity, I'll refer to your ("my machine") external > server > to be machine A, eth0 to be ip-address B, and eth0:1 to be ip-address C. > Here is how things are happening : > > Machine A sends echo request to C. > > C replies. The routing table on your multihomed server says that > the packet needs to travel out via eth0. The outgoing echo reply > therefore > will contain the source address of B. > > A is not listening for replies from B. It is listening for > replies > from C. Hence your problem. > > To see if I am right, filter tcpdump on the icmp protocol, rather > than the host of C. If you see echo replies from B coming in, and echo > requests for C going out, what I said is correct. > > Regards, > Jor-el > >
This doesn't appear to be the problem. When I ping ip address C, from machine A (my computer at a remote location) tcpdump icmp -i eth0 yields only a request. However, once I ping ip address B from Machine A it will show both the request and the reply. Also, I just looked at the syslog, which I probably should've done earlier and found the following: Jan 2 15:23:46 hostname kernel: Packet log: input DENY eth0 PROTO=1 MACHINEA:8 IPADDRC:0 L=92 S=0x00 I=0 F=0x4000 T=43 (#9) Should I be looking at the firewall as the cause of the problem. However temporarily using ipchains -P input ACCEPT and ipchains -P output ACCEPT before going back to the regular firewall settings gave me the exact same result. Do I need to specifically specifiy IP Address C in the firewall script or am I chasing a dead end? Chad