On 2004-11-09, Steve Drees <[EMAIL PROTECTED]> wrote: > John Goerzen <> wrote: >> I'm looking at redoing my mail setup due primarily to spam filtering. >> Over at http://www.tldp.org/HOWTO/Spam-Filtering-for-MX/multimx.html, >> they are suggesting not to use redundant mail servers unless needed >> for load balancing. > > This is poor advice.
Could you elaborate a bit on why that is? The author is saying that well-behaved (ie, non-spamming) MTAs would keep retrying for several days anyway, so the only time a backup MX would really prevent mail loss is due to an outage extending more than that time. What do you think? >> It seems to make a lot of sense to me, but it seems too that I must be >> missing something. > > I'd suggest having a backup MX but make sure you have all the filtering at > your backup that you have at your primary. That's what I have now, but there are some things that can't be done so well (or at the very least, only in a horribly kludgy manner). For instance, if somebody sends a message to [EMAIL PROTECTED], and it goes through the backup MX for whatever reason, the backup MX accepts the message. When it gets to the main server, it will reject it with a 550. The backup MX then has to e-mail back to the sender a bounce message. Now think what happens when viruses/spammers do this. My backup MX is sending out a lot of bounce messages to potentially innocent victims for this reason. -- John -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]