intermittent ssh connect error

[Darren Tucker]

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)
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     Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.