ssh_exchange_identification: Connection closed by remote host

TB0ne · 08-01-2013, 07:57 AM

Quote:

Originally Posted by tqisjim

Apparently, there may be a policy about responding to a 10 year old post, but this was Google's first search result.

I investigated an occurrence of this problem today. The error message seems represent a generic "failure to connect" condition reported by the client, when the sshd refused to fork more threads to handle the incoming requests. As I increased the MaxStartup setting in /etc/ssh/sshd_config, incoming requests kept consuming all the new forks, leading me to concluded the effect of a brute force ssh attack.

Thankfully, the attack is temporary, and the only long term effect is heightened paranoia. Had the attack been persistent, effective resolution would require restricting access at a network firewall.

No, there's not a policy about re-opening old threads, as long as you add something useful to it. In your case, you certainly did, and thank you for sharing the symptoms as well as the solution.

haertig · 08-01-2013, 10:48 PM

Any thoughts on what might cause this error on an intermittant (but frequent) basis? We have a very old Solaris box (5.7) at work that frequently throws this error when we try to ssh in to it. Chances are 50-50 that the ssh session will work. Try again, it might work. Try once again, it might not. Unpredictable, but very frequent. This box is specifically running a very old version of Solaris as we use it for legacy apps that have some dependency on the older OS. Apps that nobody is going to update, so we put them out to pasture on this old server until they finally die a natural death. Still, it's annoying when we can't log in to the dinosaur server reliably.

bmatusiak · 09-11-2013, 09:59 AM

i noticed i run into some ssh problems on older linx boxes because the clock battery is bad/old... try updating the time on your box.. if it works then change the cmos battery