Re: People forging their From: addresses
- Date: Wed, 30 Sep 1998 12:48:11 +0200
> For a while, I tried returning a 500 code, but I found that
> the DNS is flaky enough to actually provide false answers now
> and then, so I ended up rejecting a few messages a day who
> were otherwise perfectly legal (out of like oh 100k per day).
> So we switched back to 400 replies, so now the occasional mail
> gets delayed a bit because it gets an "unfair" 400 reply, but
> that's better than rejecting that mail altogether. Spammers
> will usually not retry even with 400 style replies when
> they're sending directly, and relays stop after a few days...
> it's bearable.
> The latter remains to be seen. Originally I used 400,
> but I found that it only led to massive and almost
> endless retries for obviously bogus domains. Then I
> switched to 500. And the loggings show that really
> existing domains are hit only very rarely.
Very rarely becomes 'quite a lot' if you have hundreds of thousands of
emails a day. If 20 valid emails get bounced by us a day, that is unacceptable.
We can not put the burden of this on our users, so we have to bear it
ourselves by returning 400. This is partly ofcourse a difference in the
customers we serve :) And upto now like JP said, for us its bearable.
Ofcourse, we have a pretty strict AUP. If we notice a spam going on from
one of our users (who are ofcourse the only ones allowed to relay through
our mailservers) then the chances are high they need to find themselves