I've been using dynastop for a week now and I still love it. First, a
quick review.
DynaStop does a reasonably good job of identifying dynamic IP addresses.
It isn't good enough that I would recommend blocking on, but it has
eliminated almost all of my image spam. The way I'm using it is:
On the lowest MX - failed lookups and dynamic IPs get a defer.
On the next highest MX number it accepts mail from these IPs but rate
limits them to 2 messages per 10 minutes.
At first it caused a major problem in that it had a false positive on
the domain secureserver.net (godaddy's servers) which also failed to
retry higher MX numbers. But I have found and fixed that. Now it seems
to just work.
The new version uses PCRE regex so it has a lot more potential than it
did last week. One of the things it needs is a rewrite of the default
config file. So if one of you regex wizards wants to rewrite this that
would really help a lot.
It can be downloaded at
http://tanaya.net/DynaStop/
Info on the new PCRE is here:
http://www.exim-users.org/forums/showthread.php?t=53579
So - who wants to jump in and do this right on the config file?