| Is there any formula or rule of thumb for working out what | smtp_accept_max should be set to. Is there any way of telling if you are
| hitting the max and users are getting connections denied ?
Sort of related, as well as smtp_accept_max, we set smtp_accept_max_per_host
to a low value (currently 5 over each of 2 MXs).
This appears to do a useful job of slowing the ratware, some of which
doesn't even bother retrying, whilst rarely delaying friendly senders who
batch mails into a single or small number of connections.
OK, a few subscribed-for bulk mail sites running abusive floodware such as
lyris or qmail get a number of of defers, but we can live with that...
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Chris Edwards, Glasgow University Computing Service