How should a reverse pointer look for an email domain

Brazen

Diamond Member
Jul 14, 2000
4,259
0
0
Some email domains are not accepting our emails because it is failing a reverse pointer lookup. So I called our ISP to have a reverse pointer record changed from their generic name to our domain, but I disagree with the tech on what the pointer should point to. Basically, one of us thinks it should point to the fqdn of the email server - mail1.company.com, and the other thinks it should point to just the domain name - company.com.

Our email addresses look like user@company.com
"host company.com" results in: company.com mail is handled by 10 mail1.company.com.
"host mail1.company.com" results in: mail1.company.com has address a.b.c.d

So should "host a.b.c.d" result in:
d.c.b.a.in-addr.arpa domain name pointer mail1.company.com.
or
d.c.b.a.in-addr.arpa domain name pointer company.com.

??
 

Crusty

Lifer
Sep 30, 2001
12,684
2
81
For the most part email servers don't care if the forward/reverse lookups match, they just check to make sure you have a reverse entry that's NOT in-addr.arpa
 

drebo

Diamond Member
Feb 24, 2006
7,034
1
81
The convention we use is the hostname of the mailserver itself. So, we would use mail1.company.com. Why? Because that's what's going to be in the headers of the email messages, not the company.com. Yes, the address is user@company.com, but no one cares about that. They care about the actual hostname of the mail server, which is mail1.company.com.

Also, you might consider adding an SPF lookup. Some mail servers like to see that and will forgive a missing reverse lookup if SPF matches.
 

kevnich2

Platinum Member
Apr 10, 2004
2,465
8
76
Originally posted by: Crusty
For the most part email servers don't care if the forward/reverse lookups match, they just check to make sure you have a reverse entry that's NOT in-addr.arpa

This is usually the case.
 

Nothinman

Elite Member
Sep 14, 2001
30,672
0
0
Basically, one of us thinks it should point to the fqdn of the email server - mail1.company.com, and the other thinks it should point to just the domain name - company.com.

Does the mail server present itself as company.com or mail1.company.com? That's what the reverse should point to and generally the latter is the case.
 

NesuD

Diamond Member
Oct 9, 1999
4,999
106
106
Originally posted by: Brazen
Some email domains are not accepting our emails because it is failing a reverse pointer lookup. So I called our ISP to have a reverse pointer record changed from their generic name to our domain, but I disagree with the tech on what the pointer should point to. Basically, one of us thinks it should point to the fqdn of the email server - mail1.company.com, and the other thinks it should point to just the domain name - company.com.

Our email addresses look like user@company.com
"host company.com" results in: company.com mail is handled by 10 mail1.company.com.
"host mail1.company.com" results in: mail1.company.com has address a.b.c.d

So should "host a.b.c.d" result in:
d.c.b.a.in-addr.arpa domain name pointer mail1.company.com.
or
d.c.b.a.in-addr.arpa domain name pointer company.com.

??


Your both right. Either the Servers FQDN or the Domain for said Email. Both will work
 

Brazen

Diamond Member
Jul 14, 2000
4,259
0
0
Originally posted by: NesuD
Originally posted by: Brazen
Some email domains are not accepting our emails because it is failing a reverse pointer lookup. So I called our ISP to have a reverse pointer record changed from their generic name to our domain, but I disagree with the tech on what the pointer should point to. Basically, one of us thinks it should point to the fqdn of the email server - mail1.company.com, and the other thinks it should point to just the domain name - company.com.

Our email addresses look like user@company.com
"host company.com" results in: company.com mail is handled by 10 mail1.company.com.
"host mail1.company.com" results in: mail1.company.com has address a.b.c.d

So should "host a.b.c.d" result in:
d.c.b.a.in-addr.arpa domain name pointer mail1.company.com.
or
d.c.b.a.in-addr.arpa domain name pointer company.com.

??


Your both right. Either the Servers FQDN or the Domain for said Email. Both will work

Alright, thanks everyone.