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- - SPF and reverse DNS for mail (http://www.howtoforge.com/forums/showthread.php?t=1404)

SPF and reverse DNS for mail

Hi all,

I start one thread for 2 problems I have at the moment. But the problems must be looked at together.

First problem:

I have set my mail-server to be reachable at mail.mydomain.dom. But when I do a reverse lookup of the IP, I get ns.mydomain.dom. Could be a problem with some mailservers.

How can I set the reverse-zone of bind, to bring mail.mydomain.dom when I do a reverse lookup? Or better, how do I set it in ISPconfig? The zone-file is generated from ISPconfig, so if I change it by hand, it will be overwritten when I do changes in ISPconfig.

My reverse-zone-file looks like this:

Code:

$TTL        86400

@               IN      SOA     ns.mydomain.dom. hostmaster.mydomain.dom. (

                                2005111601       ; serial, todays date + todays serial #

                                28800   ; Refresh

                                7200    ; Retry

                                604800  ; Expire

                                86400)  ; Minimum TTL

                        NS      ns.mydomain.dom.

                        NS      ns2.mydomain.dom.

22       PTR     mydomain.dom.

22       PTR     www.mydomain.dom.

22       PTR     secure.mydomain.dom.

22       PTR     mail.mydomain.dom.

22       PTR     ns.mydomain.dom.

22       PTR     ftp.mydomain.dom.

22       PTR     subdomain.mydomain.dom.



;;;; MAKE MANUAL ENTRIES BELOW THIS LINE! ;;;;

Second problem:

How do I use the SPF records in the right way? I have not found a description in the manuals. What to set as hostname (should this be mail?)? And what are all the other things?

I think for this to work, I need to resolve the first problem.

Quote:

Originally Posted by Lobanak

First problem:

I have set my mail-server to be reachable at mail.mydomain.dom. But when I do a reverse lookup of the IP, I get ns.mydomain.dom. Could be a problem with some mailservers.

How can I set the reverse-zone of bind, to bring mail.mydomain.dom when I do a reverse lookup? Or better, how do I set it in ISPconfig? The zone-file is generated from ISPconfig, so if I change it by hand, it will be overwritten when I do changes in ISPconfig.

My reverse-zone-file looks like this:

Code:

$TTL        86400

@               IN      SOA     ns.mydomain.dom. hostmaster.mydomain.dom. (

                                2005111601       ; serial, todays date + todays serial #

                                28800   ; Refresh

                                7200    ; Retry

                                604800  ; Expire

                                86400)  ; Minimum TTL

                        NS      ns.mydomain.dom.

                        NS      ns2.mydomain.dom.

22       PTR     mydomain.dom.

22       PTR     www.mydomain.dom.

22       PTR     secure.mydomain.dom.

22       PTR     mail.mydomain.dom.

22       PTR     ns.mydomain.dom.

22       PTR     ftp.mydomain.dom.

22       PTR     subdomain.mydomain.dom.



;;;; MAKE MANUAL ENTRIES BELOW THIS LINE! ;;;;

When you do a reverse lookup, only one record will be returned, not all your PTRs. In your case it's ns.mydomain.com. As long as get you get an answer when you do a reverse lookup everything is fine, and you shouldn't have problems with email providers such as Hotmail.:)

Quote:

Originally Posted by Lobanak

Second problem:

How do I use the SPF records in the right way? I have not found a description in the manuals. What to set as hostname (should this be mail?)? And what are all the other things?

The form for creating SPF records follows the same scheme as the one here:
http://www.openspf.org/wizard.html?mydomain=&x=27&y=5

Play around with the Openspf wizard, and you'll uderstand what you have to put into the fields.