Not enough information. You show the recieving email server, but don't say anything about the sender. 1.2.3.1 is not valid, but we'd need the domain name anyhow. I'm assuming gmail.com is not it<g>.
No, the reverse IP name doesn't have to match the MX server name, but it does have to result in a name with an A record of the same IP. It looks like maybe they are complaining about the sender address being unreachable, but without the sender address, it's hard to research. No, that is normal for multiple domains on the same IP. I don't think the reciever is broken, either. At least, I don't have enough info to say yet. Dan -----Original Message----- From: Ron [mailto:[EMAIL PROTECTED] Sent: Sunday, February 04, 2007 3:01 PM To: users@spamassassin.apache.org Subject: Sender domain must have a DNS MX I am getting the following as a bounced message when I send mail to this one person: <[EMAIL PROTECTED]>: host tane-uma.de[81.169.136.73] said: 550 5.2.1 Mailbox unavailable. Sender domain must have a DNS MX or A/CNAME record. (in reply to RCPT TO command) I have never seen anything like this for any other email I send from the same server, and I am wondering if it is something I have set up wrong, or a problem on their end. I assume this is a spam prevention technique. I run several (virtual) domains off my one server, so if they are doing a reverse DNS lookup, it is not going to return the correct domain, but I know a lot of servers do this as well. If this is indeed what they are doing, how can you set up a sever that hosts several domains off a single IP address to not fail this spam test? The other thing that might be complicating this is that server1.net (1.2.3.1) hosts email for email1.net and email2.net. But, when I send email for [EMAIL PROTECTED], server2.net (1.2.3.2) is the outgoing server. I do this so I can just manage one severs that is relaying mail from client apps (thunderbird). I don't think this is that abnormal, if not, how do I make it work correctly for this kind of spam detection? Or is the receiving server just broken? I apologize that this isn't a 100% spamassassin related question. Ron
