I don't know what server software our ISP is using. At the time of the problem, though, they didn't have the backup mail entry in place so whatever was going on was related to our primary server only. The ISP is *adamant* that the problem had nothing to do with the reverse-DNS problem and was caused only by some of the ISPs using cached DNS information that took a while to update after our mail server went live. OK in theory but it seems that doesn't explain inconsistent delivery from some of those ISPs (1 message in 10 with no bounces for the other 9). Also, 72 hours is a long time for that problem to persist - seems a long time to keep cached information. Even odder is that it went away and the mail started to flow not long after the reverse-DNS problem was corrected. I have to admit to being new to this, which is frustrating. I need to do some homework on what happens with mail servers set to what I've heard described as "paranoid mode". Barry
