Re: [exim] 421 too many concurrent sessions

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Author: Mark Elkins
Date:  
To: exim-users
Subject: Re: [exim] 421 too many concurrent sessions
I think the other thing to consider is setting "smtp_accept_max = 10"
means you can only process up to 10 e-mails at one time. If you are
doing a number of checks, Virus, multiple blacklist checks - these tests
can take a while - possible a meaningful amount of seconds each. Just
bear that in mind. You probably want to increase"smtp_accept_max" quite
a bit. I've also changed my "log selector":

log_selector = +subject +incoming_interface +incoming_port +smtp_connection

(sits in the same config area as "smtp_accept_max = 10")

Now, when tailing the exim_main.log log file, you can see what the
"Connection Count" number is. I think you'll find this useful.

2017-01-25 11:04:50 SMTP connection from [S.S.S.S]:1188 I=[D.D.D.D]:25
(TCP/IP connection count = 3)


On 24/01/2017 20:33, The Doctor wrote:
> On Tue, Jan 24, 2017 at 12:34:23PM -0500, Chris Siebenmann wrote:
>>> I cannot find the culprit doing this.
>>>
>>> Using Exim 4.88 on FreeBSD 11 I placed this into my configuration:
>> [...]
>>> smtp_accept_max = 10
>> Well, you have a limit of 10 simultaneous SMTP connections period.
>> Once you have ten active ones, any further connections will get this
>> message.
>>
>>> smtp_accept_max_per_host = 5
>> ... and a single IP can only have five connections at once.
>>
>> Note that despite the names being very similar to each other,
>> 'smtp_accept_max_per_connection' means something completely
>> different than 'smtp_accept_max_per_host'. One is about limits
>> on SMTP connections, one is about limits on MAIL commands within
>> a single connection.
>>
>> If your problem is that you cannot see where the connections
>> are coming from, look at what 'exiwhat' reports, as well as
>> ps, netstat, lsof, and other similar tools for looking at
>> network connections.
>>
>>     - cks
> Provided that the server can respond.

>


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Mark James ELKINS  -  Posix Systems - (South) Africa
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