On Mon, 20 Apr 1998, Paul Mansfield wrote:
> Please can I have clarification of this anti-spam feature.
>
> Say you have abc@xyz
>
> This feature appears to check that the 'from' field is valid by doing MX
> checks on xyz.
Yes, if by 'from' field you mean the sender address as specified in the
message's envelope - this is *not* the From: header in the message. It
is also referred to as "return path".
What it actually does with the address is to run it through the routers
or directors just as it does for delivery, except in "verification"
mode, so that some variation on what happens is possible via the
"verify_only", "no_verify", and similar driver options.
So, if you have a configured router that does MX checks for xyz when
presented with abc@xyz, then it will do them for sender_verify (provided
you haven't set no_verify on it).
> If there's no MX record for xyz, does it look for an A record for xyz, the same
> way it would for delivery.
Yes, if you have configured your router that way (which you probably
have).
--
Philip Hazel University Computing Service,
ph10@??? New Museums Site, Cambridge CB2 3QG,
P.Hazel@??? England. Phone: +44 1223 334714
--
*** Exim information can be found at
http://www.exim.org/ ***
