Hi, This is a question about DNS records and MX records and how I'm getting some weird behavior. It's not strictly speaking Declude issue, but I have a lot of respect for the people that used to hang out here and I'm hoping there's someone around who can give me some insights.
Original problem: We use Comcast for our upstream provider. A few years ago, when we switched to them from our telecom provider, they told us that their DNS servers would sometimes intercept DNS calls even though we have our own DNS server. This was supposedly because we only rent a small IP subnet from them. At the time, they had us send copies of our zone records to them so that their DNS servers would have the same information as our DNS server. This worked fine until this fall, when we installed a new mail server on a new IP address. Our DNS server, of course, was updated to reflect this change. However, mail sometimes shows up at the old mail server anyway, in a more or less random pattern. It apprears to me that most of the time when people send mail to us, their mail servers correctly getting the IP address resolved by our DNS server. However, about 25% of the time, it appears that the DNS request from those sending mail servers receives an outdated response from some unidentified Comcast DNS server, resulting in the wrong IP address and the mail ends up going to our old mail server. Suppose, for example, that you send a message to imailad...@bcwebhost.net (the address I'm using here, which is a misnomer since our new mail server is running SmarterMail). The MX records for bcwebhost.net points to mail.bcwebhost.net and the A record mail.bcwebhost.net points to our new server IP (ending in .200). So your email should arrive at our new mail server. However, sometimes it will arrive at the old mail server named mail2.bcwebhost.net (IP ending in .193). The old DNS records had the bcwebhost.net MX record pointing to mail2.bcwebhost.net, for which the A record pointed to .193 (the old server). I've been going in circles for about a month with Comcast on this and they don't recall that they're the ones who told me three years ago that they sometimes intercept DNS calls. I was wondering if anyone has any ideas or suggestions on how to track down the errant DNS calls? Second problem: In our new DNS records, I have it set up something like this: two MX records: bcwebhost.net MX mail.bcwebhost.net mail.bcwebhost.net MX mail.bcwebhost.net one A record: mail.bcwebhost.net A (IP.200) Is there any reason I can't have the same name for both an MX and an A record (in this case, mail.bcwebhost.net)? The Comcast people claimed this was wrong and that the MX record should point to an IP address directly instead of a host name (which I'm sure is wrong). They tried to claim that this is the cause of my original problem but even if they're right about this, then it still doesn't explain the original problem. Thanks, Ben --- This E-mail came from the Declude.JunkMail mailing list. To unsubscribe, just send an E-mail to imail...@declude.com, and type "unsubscribe Declude.JunkMail". The archives can be found at http://www.mail-archive.com.
