DNS/rDNS Bounce

[DuaneMIS]

Hello,
I will appologize if this is simular to prevous postings, I cant beleive I am the first to deal with this...

When we try to send mail to Craigslist from our Exchange Server we get the following Error:

1/28/2008 4:03 PM
There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.
<m-i-s.com #5.5.0 smtp;554 <unknown[66.214.45.118]>: Client host rejected: rDNS/DNS validation failed. Please setup matching DNS and rDNS records: http://bind8nt.meiway.com/itsaDNSmess.cfm>

I have my public website hosted with a hosting company www.m-i-s.com on public ip 74.32.90.4

My exchange server is on a dedicated IP from Charter at 66.214.45.118, and a PTR record of mail.m-i-s.com
we have additional a records for corp.m-i-s.com that point to 66.214.45.118
Finally our incomming MX record points to mail.global.frontbrige.com who provides spamfiltering, redundancy and backup services.

The headers in my outbound e-mail show the server name as m-i-s.com. I beleive what is happening is Craigslist is looking at m-i-s.com and resloving that as www.m-i-s.com and comming up with 74.90.32.4 and then doing a rDNS and not comming up with mail.m-i-s.com thus bouncing the mail.

Am I understanding the process, and how do I correct it? THANK YOU SO MUCH IN ADVANCE,

 

[nobaloney]

It appears the problem is fixed; your reverse DNS appears to be right now.

I don't know why you thought posting on our forum would help you; we're a forum for users of a linux/unix based control panel.

And there are at least a dozen (perhaps more) posts on our forum explaining the problem and the fix. Did you search our forum for reverse DNS?

Bottom line: If you're sending mail from a server that identifies itself in it's helo/ehlo message as mail.m-i-s.com, then craigslist is going to do a lookup on mail.m-i-s.com. Then it's going to do a lookup on whatever IP# the first lookup returned. That must return something. According to RFCs it can return anything as long as it returns something, but many mx servers require it match the helo/ehlo identified hostname.

Jeff