SMTP Mail server only delivering to certain domains

Posted on 2009-12-17
Medium Priority
Last Modified: 2013-11-30

I have a situation where the our IIS server using SMTP is only delivering mail from the Pickup directory to some email domains.  Emails domains like gmail.com and yahoo.com both work, but other ones are not working.  The email appears to go (disappears from the pickup directory) and no error messages are given that I can find.  
Windows 2003 Server Service Pack 1
SMTP Protocol 6.0

Any help would be appreciated.
Question by:sharpapproach
  • 3
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Expert Comment

ID: 26077994

The mails will bounce back in next couple of hours.

It seems to me that you didn't created the server ptr (Reverse DNS) record that's why you are facing this problem.


1. Set your server name as a FQDN (server.domain.com.)
2. Update your DC to create

Server.domain.com ptr record to your server IP which you have given in IIS SMTP settings

3. Create

server.domain.com A xx.xx.xx.xx (SMTP Server IP)

Mail will start deliver to all the mail domains in next few hours.
LVL 27

Accepted Solution

shauncroucher earned 2000 total points
ID: 26078781
There is not enough information to work with here.

Check your public IP is not on a blacklist using mxtoolbox.com --> blacklists.

What are you using as the 'sender' address, are there any NDR's delivered to this email address?

Check that you have a PTR record setup, but most likely this will be with your ISP if it is not setup.

The reverse DNS (rDNS \ PTR) record is configured by the people who issued your IP address in most instances (so your ISP).
Below are two articles which explain the general requirements for reverse dns (rDNS\PTR) records for your IP address.
I try to adhere to the following when setting up a rDNS (PTR) record:
Be a Fully Qualified Domain Name (FQDN) such as server.domain.com (not just 'domain.com' or 'server').
Should not contain 'in-addr-arpa' and should not include words like pool or dyn etc.
Should match what you use in your SMTP HELO\EHLO hostname if possible.
For neatness and as a good rule of thumb, if your incoming mail is delivered to the same server that you use for Outgoing you should make sure all the following FQDN's match:
MX record
rDNS (PTR) record
SMTP EHLO hostname
http://www.amset.info/exchange/dnsconfig.asp (Courtesy of EE member Mestha)


Author Comment

ID: 26081579
Still no luck some more information:

The server is not using Exchange for mail delivery.
SPF record has been created.

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LVL 27

Expert Comment

ID: 26081682
What are the answers to my questions:

Check your public IP is not on a blacklist using mxtoolbox.com --> blacklists.

What are you using as the 'sender' address, are there any NDR's delivered to this email address?

Check that you have a PTR record setup, but most likely this will be with your ISP if it is not setup.


Author Comment

ID: 26082057
1.  The public IP is on two blacklist - SPAMCANNIBAL and NOMOREFUNN out of the approx 40 listed.
2.  Sender address can be any valid email address, no NDR delivered to this email when email is sent to a valid email address.   When an invalid address is used as a receiving email address an NDR comes in to the administrator
3.  There is a PTR record in the reverse lookup zone.

What still is baffling is the email is consistently going to yahoo, gmail but not other domain names.   Your help is appreciated.
LVL 27

Expert Comment

ID: 26082293
OK, nothing baffling here at all.

You are on at least 1 blacklist so you can expect irratic delivery. It all depends on which blacklists the destination are using.

If you are on at least 1 blacklist that will be the problem.

You need to register to me removed from the lists and then find out why you are on them in the first place. Check that the SMTP server is not an open relat etc.

Use Diagnostics from mxtoolbox.com


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