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SMTP Reverse DNS Mismatch

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Hello I am using Exchange server 2007.

I am not able to send mails to few domains.
for example yahoo rediff no issues but with hotmail i am not able to send or receive.

In mxtoolbox i have checked my exchange server ip address for blacklists.
I am getting 4 timeouts.
and also i am getting SMTP Reverse DNS Mismatch.
Please do refer attachment.

Is it issue with configuration or my exchange server is blacklisted.
If it is blacklisted what is procedure to remove my server ip from blacklist

mercredi 9 janvier 2013 09:56

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Yes, have you ever used nslookup?

http://support.microsoft.com/kb/200525?wa=wsignin1.0

----------------------

Here's an example (slight edited):

[PS] C:\>nslookup
Default Server: DC1.mynet.lan
Address: 10.0.0.10

> set q=ptr
> 11.20.30.15
Server: DC1.mynet.lan
Address: 10.0.0.10

Non-authoritative answer:
11.20.30.15.in-addr.arpa name = mail.my-domain-here.net

------------------------------

In case you are wondering, these commands are equivalent:

set q=ptr

set type=ptr

set querytype=ptr

-----------------------------

Anyway...

1. the IP address configured by your ISP for your PTR record should match the external interface (mailserver or firewall) from which email is sent to the outside world.

2. The domain name shown by the PTR query should be what is indicated on the general tab of the Send Connector properties (HELO/EHLO setting).

Please mark as helpful if you find my contribution useful or as an answer if it does answer your question. That will encourage me - and others - to take time out to help you.
- Modifié David M (LePivert) vendredi 11 janvier 2013 14:17
- Marqué comme réponse Risingflight mercredi 15 janvier 2020 07:44
vendredi 11 janvier 2013 14:14

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Have you created a PTR record on the external DNS server pointing back to your server.
Sukh

mercredi 9 janvier 2013 22:04
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"Most SMTP servers will accept your mail if you simply have a reverse DNS entry. It does not have to match the domain name on your e-mail address. Some SMTP servers will reject mail if the reverse DNS doesn't match the HELO/EHLO hostname used in the connection. If your mail server's hostname is mail.example.com then your reverse DNS, MX record, HELO/EHLO, and SMTP greeting banner should all be mail.example.com as well."

From:

http://serverfault.com/questions/24943/reverse-dns-how-to-correctly-configure-for-smtp-delivery

----

If you look at your Send Connector, General Tab (Organization level, HT), what do you have for the HELO/EHLO setting?

If I recall correctly, that should match the target of your reverse DNS record, i.e.

11.22.33.44 -> mail.contoso.com

http://2.bp.blogspot.com/_8cKJgEQ3LNM/SsHQap_Q67I/AAAAAAAAAAM/OegrQW5txx4/s320/sendconnector.png

IP address in the PTR record should match the one used to send mail from your organization, either that of your mail server or, more likely, that of the external port on your firewall (if you use 1 to 1 NAT).

Please mark as helpful if you find my contribution useful or as an answer if it does answer your question. That will encourage me - and others - to take time out to help you.
- Modifié David M (LePivert) mercredi 9 janvier 2013 22:20
mercredi 9 janvier 2013 22:13
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Oh yes, timeout does not indicate you are on a blacklist. I have not tried recently, but I believe I too have timeouts against a certain number of these websites.
Please mark as helpful if you find my contribution useful or as an answer if it does answer your question. That will encourage me - and others - to take time out to help you.

mercredi 9 janvier 2013 22:14
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I have checked for smtp on the website dns queries , i am getting this errors.

I am using exchange server 2007. please guide me to resolve this issue ASAP

jeudi 10 janvier 2013 09:47
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I have checked for smtp on the website dns queries , i am getting this errors.

I am using exchange server 2007. please guide me to resolve this issue ASAP

jeudi 10 janvier 2013 09:47
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As mentioned before it seems like you have not created the PTR record?
Sukh

jeudi 10 janvier 2013 09:55
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Do guide me where to create the pointer record and how to create. In my exchange 2007 server or at the ISP DNS.

jeudi 10 janvier 2013 16:46
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http://support.microsoft.com/kb/300171
Sukh

jeudi 10 janvier 2013 16:48
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Please contact your ISP and ask them to create a PTR record for you. Not something you create on your Exchange server.
Please mark as helpful if you find my contribution useful or as an answer if it does answer your question. That will encourage me - and others - to take time out to help you.

jeudi 10 janvier 2013 18:10
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Sorry forgot that bit, has to be done on your external DNS and if you manage your external DNS then you can create it yourself.

It's all in that KB anyway.
Sukh

jeudi 10 janvier 2013 18:22
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Hello

I spoke with the ISP and they said that the PTR record is available.

I am getting mails from some domains and from some domains i am not getting.

any configuration that i should do on my exchange.

Please guide me

vendredi 11 janvier 2013 04:14
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Have confirmed and actually seen how it has been setup and does it match your external IP?
Sukh

vendredi 11 janvier 2013 10:11
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Yes, have you ever used nslookup?

http://support.microsoft.com/kb/200525?wa=wsignin1.0

----------------------

Here's an example (slight edited):

[PS] C:\>nslookup
Default Server: DC1.mynet.lan
Address: 10.0.0.10

> set q=ptr
> 11.20.30.15
Server: DC1.mynet.lan
Address: 10.0.0.10

Non-authoritative answer:
11.20.30.15.in-addr.arpa name = mail.my-domain-here.net

------------------------------

In case you are wondering, these commands are equivalent:

set q=ptr

set type=ptr

set querytype=ptr

-----------------------------

Anyway...

1. the IP address configured by your ISP for your PTR record should match the external interface (mailserver or firewall) from which email is sent to the outside world.

2. The domain name shown by the PTR query should be what is indicated on the general tab of the Send Connector properties (HELO/EHLO setting).

Please mark as helpful if you find my contribution useful or as an answer if it does answer your question. That will encourage me - and others - to take time out to help you.
- Modifié David M (LePivert) vendredi 11 janvier 2013 14:17
- Marqué comme réponse Risingflight mercredi 15 janvier 2020 07:44
vendredi 11 janvier 2013 14:14
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i have checked nslookup. i dont see any issues

can you send me your email id i will forward you the domain name

samedi 12 janvier 2013 09:46
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Can you post the ndr when you send? & turn up protocol logging on the send connector?c
Sukh

samedi 12 janvier 2013 12:21

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