Francesco Abeni wrote: > Good morning everyone, i'm in charge of reducing SPAM at a customer > site. Already have SPAMASSASSIN, sa-update weeklyexecuted. > > I'd like to implement a "Bogus MX" for further filtering of SPAM. I > don't know if this is the correct name, by "Bogus MX" i mean setting > up a low priority MX record which points at a non-smtp server. > > I'd like to know some first-hand experience about two questions. > > 1. Has it caused any lost mail issue or client complaints? > I know every half decent mail server should try other MX. In real > life, have you often received complaints from valid senders? > > 2. Has it reduced significantly SPAM? > I'd like to know if it's worth the (little) trouble of setup and > verifying question #1. > > Thank you for your time.
I would say that it is too risky to put a non-smtp host as your primary MX. There are some servers which will have a problem with that setup and either be unable to deliver mail to you or delay the mail. Another option is to do this as a secondary MX record. Many spam sources tend to prefer the higher priority servers on the assumption that they may not be as well protected as the primary server. I am doing this as a side effect of disabling my secondary server and never replacing it. I haven't had any problems. Something else that can be useful is using an MTA blacklist. I use the zen.spamhaus.org blacklist on my MTA. I resisted using an MTA blacklist for a long time, but the spam volume finally got to be too much, so I implemented this one since it seemed to be the most reliable. It cuts down on my spam considerably and I haven't had any complaints about blocked emails yet. It blocked almost 14,000 emails yesterday on my server, which is over 10x the amount of mail that made it to the users' mailboxes (and over 60% of that is marked as spam). -- Bowie
