Hey Bill,
Am 14.10.2016 um 13:41 schrieb Bill Pye:
> Thanks for your comments. I'm not saying that the backup mx has no anti-spam
> systems installed (I believe it does) it's just that I don't have any control
> over that server.
In my experience *any* mismatch in configuration between backup mx + "main"
mailserver will come back to haunt you. In the best case you will get more
spam which was accepted by your backup MX.
> it's a short term solution to any interruption toandy mail server being offline,
IMHO: Don't worry about loosing messages just because your server is offline
for some hours (assuming you can tolerate not being able to receive mail for a
few hours).
(YMMV - special servers/requirements/... ).
> I know the problems
> with a backup MX but I'm really just finding my way around rspamd at the
> moment and seeing how effective/useful each feature is in my environment. Back
> to my original question, does greylisting serve any useful purpose in this
> situation - I'm leaning towards disabling it.
As long as your backup MX behaves differently than your main mail server there
is no use in rejecting/deferring anything at SMTP time.
Personally I don't use greylisting because rspamd is effective enough for me.
If I feel that spam recognition rates will drop too much, I will enable it as
rspamd has grown some support for it (AFAIU even for mail clusters due to
reddis). I assume the main advantage is to wait if host sending a "suspicious"
message ends up on a few DNS blacklists which should happen pretty quickly for
typical spam senders.
Felix