create new tag
, view all tags
Collecting notes and resources about the interaction of DNS with email, especially the DNS PTR record which deals with whether an emailer's home site (address) "resolves".




from a Slashdot thread by FreeLinux:

That's completely wrongheaded. Mail should be delivered.

I guess that you are entitled to your opinion but, I feel that the action is correct. The fact is that this policy works very well for me. The mail does go through, eventually.

Here's how it works. A user tries to send a message to someone inside my company. The message fails, of course, because my mail server rejects the connection due to the lack of a PTR. After a few attempts the sender either calls their admin or the intended recipient, who then calls me. Either way, the admin and I talk. He/she says your mail server is broken. I say no, it isn't, yours is misconfigured. Try sending a message from your Yahoo account and you will find that it is delivered. He/she then says, so why can't I send any mails to your domain. I respond that it is because your DNS is misconfigured. Call your ISP and ask them to add a PTR record for your mail server and the mail will flow.

Sometimes there is question about this along the lines of; well why can I send to these other domains? I explain that some administrators are willing to accept mail from misconfigured systems because there are so many of them and it makes the administrator's life easier. I then say; Trust me, call your ISP. It only takes a couple of minutes and you will never have to deal with this problem again.

Typically, I get a thanks via email the next day. If they refuse to make the changes I point out to my user that they are receiving mail from everywhere else just fine and they can even send to this broken domain. Thus, our mail system is working correctly and the problem is at the far end. Done.


See Resource Recommendations. Feel free to add additional resources to these lists, but please follow the guidelines on ResourceRecommendations including Guidelines_for_Rating_Resources.


  • (rhk) [[][]]; ; —
  • (rhk) [[][]]; ; —
  • (rhk) [[][]]; ; —

Recommended for Specific Needs

  • (rhk) [[][]]; ; —
  • (rhk) [[][]]; ; —
  • (rhk) [[][]]; ; —


  • () RandyKramer - 20 May 2003
  • If you edit this page: add your name here; move this to the next line; and if you've used a comment marker (your initials in parenthesis), include it before your WikiName.

Page Ratings

Topic revision: r1 - 2003-05-20 - RandyKramer
  • Learn about TWiki  
  • Download TWiki
This site is powered by the TWiki collaboration platform Powered by PerlCopyright 1999-2017 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding WikiLearn? WebBottomBar">Send feedback
See TWiki's New Look