[resolved] ssh works via cable but not via wifi

fimblo · Last edited by fimblo on Mon Oct 25, 2004 4:20 pm; edited 1 time in total

I've got a rather strange ssh problem...

I have a laptop with two nics, one wireless (eth1) and one wirefull (eth0). eth0 is connected via cable to a switch, from there to my server. eth1 is connected via radio to the switch (which talks 802.11b) and there to the same server. This server is my workstation with postfix, httpd, and also runs iptables sharing my single public ip via nat to my internal network.

When eth0 is activated, and eth1 is down:
* I can ssh to my server, do everything I normally do (connect outwards, send email, etc)

When eth1 is activated and eth0 is down:
* I can surf, send email, ssh to other servers on the internet, but
* I cannot ssh to my server.

wtf?
I also tried ssh'ing to another workstation, and from there ssh'ing back to my server - for some strange reason it doesnt work either. When connecting via ethernet cable, this works...

I first thought this might be due to a messed up iptables conf, but after this last test I just cant figure it out...

Some logs:

JPMRaptor · Guru Joined: 04 Oct 2002 Posts: 410 Location: Maryland

Nothing aparent to me in the client side log. Is there any log output on the server side?
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TheOtherShoe · n00b Joined: 12 Oct 2003 Posts: 47 Location: Portland, OR

I don't know a lot about SSH, so I may not know what I'm talking about here. However, it could be that your server is checking a client identification key,which is the same whichever interface you use to connect. But your two interfaces are presumably connecting from different IP addresses. The server could be noticing this discrepancy and assume that it is being spoofed, so it refuses the connection to the wireless interface. If you connected with the wired interface the first time you set this up then that is the IP address that a key would have been established with, so that interface would be determined to be valid.

I know that this is a problem if the server switches interfaces; you have to erase the known hosts file on the client to prevent it from thinking it is being spoofed. I'm not positive that the same thing happens going the other way though. So, just a thought I guess.

fimblo · Posted: Mon Oct 25, 2004 4:19 pm Post subject: SOLVED

blush, I solved the problem- I had recompiled libc, but forgotten to restart sshd.

after I restarted it, everything worked properly

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