IBBoard wrote:
I've been looking around but so far haven't been able to find anything
(partly because it's difficult to phrase a search query!). If someone
has a solution/config for this then that'd be great.
Before anyone points out issues with GMail and lack of control, this is
all being done on a domain on a VPS. I'm just using my Gmail address for
the mailing list :)
Basically, 99% of the spam I get (which is only a small amount compared
to some people) is either a) purporting to be from me, to me or b) has a
date that Thunderbird reports as 1976 or 2038 (but is really 3609 or
just "38"). I've resolved the first part with SPF records and checking
them in Postfix, but I can't work out how to get Postfix to reject mail
that is outside a 14 day window from today (or silently dispose of it if
it's not possible because it has to get too far in to the system to fail
it).
You need a content filter for this. Header checks can do this; however,
they're static, so you have the problem of updating them constantly to
keep the validity window moving. Plus there's the issue of date
formats. The best way, IMO, is a policy service that can grok a wide
variety of date formats and check if the date is within 14 days of the
current time.
There are spamassassin rules for future dates in message headers, so you
might try that route instead of rolling your own.
