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Not sure what I'm missing, but my current company machine is unable to SSH to an AWS instance we have running for a project. Here are the particulars:

  • Other folks in my organization (and from my office) can SSH to it, using their hardware
  • I have done so in the past, as recently as a week and a half ago
  • I can SSH to internal servers (ie ones inside our firewall)
  • All other traffic that has to go through the firewall seems to work fine (e.g. I can curl from the command line to the AWS server in question w/o problem)
  • Mac version is OS X 10.7.4

Running ssh with the -vvv command yields little to help me:

$ ssh -vvv
OpenSSH_5.6p1, OpenSSL 0.9.8r 8 Feb 2011
debug1: Reading configuration data /etc/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to [**.**.**.**] port 22.
debug1: connect to address **.**.**.** port 22: Operation timed out
ssh: connect to host **.**.**.** port 22: Operation timed out

Not sure where else to look. I thought it might be a proxy thing, but a) I haven't changed proxy settings afaik, and b) others w/ the same proxy settings aren't having the same problem.

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Do you see a banner if you telnet the host on port 22? – James Yale Oct 23 '12 at 15:12
Are you on a different IP address? Verify that the Security Group for that AWS instance allows SSH traffic for your IP. – cjc Oct 23 '12 at 15:26
@James Telnet hangs just like SSH on port 22. – Paul Oct 23 '12 at 16:05
@cjc I don't know how my company routes our traffic, it's a pretty good sized company. Nothing that I know of has changed on the AWS security group, but I'll have the admin verify that. – Paul Oct 23 '12 at 16:08
@Paul, note that Security Groups can be applied to more than one instance (in fact, that's the whole point of SGs). Yes, check with your admins. – cjc Oct 23 '12 at 16:16

Can you telnet to port 22 on that server? Guessing not, but it's worth a try. If you can't, do you have the same external IP as the other servers? If you do it's probably a local firewall somewhere. If you don't, I'm guessing you've accidentally blocked yourself on the external server. Check /etc/hosts.deny for your IP address, and possibly iptables on it.

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No, can't telnet. and the problem is more than one external server, reducing the odds that it's me being blocked by that one server. – Paul Oct 23 '12 at 16:04
up vote 0 down vote accepted

OK, looks like the problem was that I was trying to SSh into the elastic IP vice using the dns name of the AMI in question. Not sure why it worked before and not now, but there it is.

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