Linode.com Forum

[Clapper]

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.postfix.users/browse_thread/thread/b693dfa514bfeded/71b88f7773459269?lnk=st&q=(in+reply+to+RCPT+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?

[TehDan]

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

[Clapper]

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

[TehDan]

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/

[Clapper]

I was just impatient. You were right, after 24 hours looks like my messages are now being delivered!

Thanks!