intermittent ssh connect error

[Paul Archer]

As the kid in "The Incredibles" says: "That was totally wicked!"
Thanks much for helping me to solve what had been a long-standing and very 
annoying problem. (That'll teach me to pay more attention to every config 
option at the application layer before I go blaming the network, too.)

Thanks again,

Paul

--------------------
     Paul Archer
Senior Unix SysAdmin
     Masergy, Inc.
     214-442-8827
parcher at masergy.com
--------------------

On Thu, 18 Oct 2007, Darren Tucker wrote:

> Paul Archer wrote:
>> We've got set of servers that use AFD (http://www.dwd.de/AFD) to scp files 
>> to a set of receiving servers. There are about 25 sending machines, and 12 
>> receiving machines. All the servers are RHEL 4 and 5, with the senders 
>> running openssh 4.3p2, and the receivers running 3.9p1.
>> 
>> Most files are sent without a problem, but on a pretty regular basis, we 
>> get "ssh_exchange_identification: Connection closed by remote host" in our 
>> log files on the senders.
>> The odd/interesting thing is that while that error often shows up on a 
>> connection to one machine, we also get bursts, where the error happens on 
>> connections to several different machines at once. That leads us to think 
>> it's an issue on the sending side, rather than the receiving side.
>
> I suspect you're hitting the MaxStartups unauthenticated connection limit. 
> It default is 10, try bumping it on the servers to, say, 30 or 40.
>
> -- 
> Darren Tucker (dtucker at zip.com.au)
> GPG key 8FF4FA69 / D9A3 86E9 7EEE AF4B B2D4  37C9 C982 80C7 8FF4 FA69
>    Good judgement comes with experience. Unfortunately, the experience
> usually comes from bad judgement.
>