OpenBSD lists wrote:
Most of the spam I've received from marketing companies tends to come
from send-only servers (looking at the user-agent of the sending server
its some kind of Python library intended for just sending pre-formatted
messages to a list of recipients).
What I've done is constructed a script that while spmad is stuttering
their connection, it connects back to the sending server on port 25 and
executes an EHLO. If the sending server doesn't respond to the EHLO, it
runs pfctl to add that server's address to a block list.
That will block a LOT of legitimate e-mail also. Including
semi-legitimate e-mails like this one... Why should all e-mail servers
accept connections from the outside?
Mikkel
