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View Full Version : sshd problem with FC4 and Dlink f/wall?


gregdog
2005-10-11, 08:49 AM CDT
Maybe a networking / ssh guru can explain this one: ssh connections from my home net thru a Dlink router work to a Mandrake box, but not to an FC4 box.

- I have an FC4 box 'phoenix' and a Mandrake box 'insecure' attached to the Internet (outside my office firewall).
- I can ssh to phoenix and insecure w/no problem from my Win 2k PC on the same exposed subnet and from within my office firewall.
- From my HOME network I can ssh into insecure but NOT into phoenix from a variety of machines (win2k, XP, FC4). My home LAN is behind a DLink firewall.

Phoenix is running an iptables firewall, but I can prove that it's accepting the ssh connections by logging the 'accept' rule, and in fact it doesn't matter if I turn the firewall off altogether. I've also turned off SELinux with no improvement (except that my iptables logging stops)

My hosts.allow file on phoenix is allowing all incoming ssh (sshd:ALL), but when I turn on debugging in sshd it logs no messages when connecting from boxes behind my DLink f/w.

The connection from my home LAN to phoenix seems to be getting lost between iptables and sshd. Can anyone tell me what's happening here? In fact, if anyone wants to try ssh to 216.214.99.171 and let me know if they get a login prompt, I'd appreciate it!

gregdog
2005-10-13, 09:36 AM CDT
Well, seems there are no networking / ssh gurus out there who read this or want to help.

I finally found the problem: after reloading the phoenix box with FC4 from scratch and putting a 3rd FC4 box into the equation (worked perfectly) I realized that the phoenix box has a routing "anomaly" - it has 2 interfaces & the default gateway in use was the wrong one. The ssh connection was coming in thru one gw and responses were going out thru another. Something, somewhere, silently objects to that, and I'm not sure which side of the ssh connection it is. Now I've set the default gw to the "real" internet gateway everything works fine....