intermittent ssh connect error

Paul Archer parcher at
Sat Oct 20 00:37:47 EST 2007

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 Archer
Senior Unix SysAdmin
     Masergy, Inc.
parcher at

On Thu, 18 Oct 2007, Darren Tucker wrote:

> Paul Archer wrote:
>> We've got set of servers that use 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
> 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.

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