Once upon a time, Ken Smith <kens at kensnet.org> said: > In this case the secondary MX has the same RBL's etc etc as the > primary. I do see the spammers sending their junk to the secondary > more than the primary MX. Agree the secondary does not know the > difference between valid and invalid addresses. That's a big "bad idea". Aside from spam filtering, your backup will accept invalid recipients and then (when delivery to primary fails) generate bounces back to senders. This is known as "back scatter" and will get your server black-listed. If you don't have a network name service of some type (e.g. LDAP), don't do this. The real question is: what are you trying to achieve with a backup MX? If it is to store mail when the primary is down, legitimate remote mail servers will do that for you; you don't need to have a backup. -- Chris Adams <linux at cmadams.net>