Well I meant huristically but the spell checker got me there and perhaps made a point! Yes I am thinking of smtp_max_per_host, but in order to set that you need to know what max should be in the context of these settings…. I think given what you say I will up them a bit but set smtp_max_per_host to the current smtp_max_accept which no host should notice and hubristically change this if it causes a problem!
Best/Rob
On 9/26/17, 12:26 PM, "Exim-users on behalf of Jeremy Harris" <exim-users-bounces+r.bannocks=arts.ac.uk@??? on behalf of jgh@???> wrote:
>On 26/09/17 11:55, Robert Bannocks wrote:
>> In respect of smtp_accept_max is there some upper limit and, for RH Linux, how do I find out what this may be. There is presumably some Kernel limit, but there are other things to consider too. Is this just something people adjust hubristically or is there a more scientific approach?
>
>I like the suggestion of hubris...
>
>The kernel limitation is essentially 64k minus any reserved via
>ip_local_port_range and ip_local_reserved_ports sysctls.
>
>Exim has a hardcoded limit of 4k (obviously individual distros could
>vary the code, but there's no support in build documentation for doing
>so. Memory is pre-allocated for connection-tracking purposes in
>proportion to the configured value, so you don't want it too high.
>
>The practical limit will be your system load, dealing with the number
>of concurrent connections.
>
>>
>> Same question for smtp_connect_backlog.
>
>This is just the value given with the "listen" syscall to the kernel.
>See the comments in the docs.
>
>>
>> Do not assume what I have inherited makes any sense.
>
>If your problem is with certain individual source systems, consider
>the smtp_max_per_host config option.
>
>--
>Cheers,
> Jeremy
>
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