Linode Forum :: PRT Record?? Remote mailserver won't accept my mail.

As you know, normal DNS takes a hostname and returns an address. There is also RDNS (Reverse DNS) - RDNS takes an IP address and returns a hostname - it uses PTR (PoinTeR records) to do this.

For mail to work you have to set rdns - this is done in the Linode Platform Manager rather than with zoneedit - because you're doing things backwards: associating and IP address (owned by linode) with your domain (owned by you).

Mailservers look up PTR records to stop basic spam techniques - spammers liying about hostnames to try and avoid detection.

Hope this helps,

Dan

Author:	Clapper [ Sun Sep 25, 2005 4:51 pm ]
Post subject:	PRT Record?? Remote mailserver won't accept my mail.
I am using Zonedit and Linode for a while, and basically my mail and everything resolves and works ok. www.hiddenworld.net However, I had trouble getting another mail server to accept my messages. Here is their rejection response in my log (yyy.yyy.. is my ip address): Code: > host mail.anotherdomain.com[xxx.xxx.xxx.xxx] said: 450 > Client host rejected: cannot find your hostname, > [yyy.yyy.yyy.yyy] (in reply to RCPT TO command) This thread says I need PRT record: Quote: http://groups.google.com/group/mailing. ... TO+command)+postfix+said:+450+Client+host+rejected:+cannot+find+your+hostname,&rnum=1&hl=en#71b88f7773459269 Is that a part of Postfix configuration, or do I need to change something in my Zoneedit record? I guess the remote host can't resolve my IP to an address? How can I resolve?

Author:	TehDan [ Sun Sep 25, 2005 5:19 pm ]
Post subject:
As you know, normal DNS takes a hostname and returns an address. There is also RDNS (Reverse DNS) - RDNS takes an IP address and returns a hostname - it uses PTR (PoinTeR records) to do this. For mail to work you have to set rdns - this is done in the Linode Platform Manager rather than with zoneedit - because you're doing things backwards: associating and IP address (owned by linode) with your domain (owned by you). Mailservers look up PTR records to stop basic spam techniques - spammers liying about hostnames to try and avoid detection. Hope this helps, Dan

Author:	Clapper [ Sun Sep 25, 2005 7:27 pm ]
Post subject:
TehDan wrote: As you know, normal DNS takes a hostname and returns an address. There is also RDNS (Reverse DNS) - RDNS takes an IP address and returns a hostname - it uses PTR (PoinTeR records) to do this. For mail to work you have to set rdns - this is done in the Linode Platform Manager rather than with zoneedit - because you're doing things backwards: associating and IP address (owned by linode) with your domain (owned by you). Mailservers look up PTR records to stop basic spam techniques - spammers liying about hostnames to try and avoid detection. Hope this helps, Dan Thanks for that! Can you direct me to Linode Platform Manager so that I can make the corrections? In my "member's home" page, I have already set the reverse DNS, but it sounds like you are refering to something else... Thanks! Jeff

Author:	TehDan [ Mon Sep 26, 2005 5:28 am ]
Post subject:
Members page is the right place (LPM is just the fancy name...), the change can take about 24 hours though. Try typing "host <your ip>" at your command prompt to check your RDNS - you'll either see your domain (in which case its done) or a linode domain (in which case the changes haven't propogated yet. if you don't have host installed, its in the bind9-host package in debian, you can also check them online at http://www.samspade.org/t/

Author:	Clapper [ Mon Sep 26, 2005 11:14 am ]
Post subject:
I was just impatient. You were right, after 24 hours looks like my messages are now being delivered! Thanks!

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