Mail Flow Troubleshooting


Mail flow issues should be troubleshot by first determining what direction the issue

  • Internal to Internal
  • Internal to External
  • External to Internal

MX Record – You need to make sure that the MX record for you domain points to a host record that points to your IP

Example(purely theory): If my IP was 65.55.88.22 and my domain is Domain.com then I my MX should look something like this

Domain Pref Hostname IP Address TTL
Domain.com 10 mail.domain.com 254.63.63.63 60

Services

Make sure the services are running (in order 2003, 2007, 2010)

Capture

image

 image

Firewall

Email uses port 25(SMTP) primarily for mailflow, you need to be sure that port 25 is forwarded through your firewall to the exchange server
Also if you have (you can test with MXtoolbox.com or Manual SMTP test (below) to verify that you can get to the mail server.

Accepted domains

In order to receive mail to a domain name you need to have that name listed in the  accepted domains (2007\2010)

image 

Email Address Policy (2007\2010)

In addition to the accepted domains you need your users to have the domain address stamped on the users, to do that you need to add it to the Address Policy

(Left is 2010\2007, Right is 2003)image

image image

image

Next -> Next -> Finish

Active directory lookups

Make sure you can access a Global catalog Domain controller in your site

Also make sure that replication is ok between servers
(Active Directory Sites and Services -> Site Name -> Servers -> ServerName -> NDTS Settings -> Rt Click the connection in the right window and choose “Replicate Now”)

Manual SMTP Testing (Red TXT is typed commands)

Click Start -> run -> CMD (enter)

telnet mail.domain.com 25220 mail.domain.com Microsoft ESMTP MAIL Service ready at Sat, 19 Dec 20
09 15:57:35 -0600
ehlo domain.com
250-mail.domain.com Hello [192.168.3.10]
250-SIZE
250-PIPELINING
250-DSN
250-ENHANCEDSTATUSCODES
250-STARTTLS
250-X-ANONYMOUSTLS
250-AUTH NTLM
250-X-EXPS GSSAPI NTLM
250-8BITMIME
250-BINARYMIME
250-CHUNKING
250-XEXCH50
250 XRDST
mail from: me@domain.com
250 2.1.0 Sender OK
rcpt to: administrator@domain.com250 2.1.5 Recipient OK
data
354 Start mail input; end with <CRLF>.<CRLF>
this is a test
.
250 2.6.0 <f23d11e3-fcac-4033-8450-9f1b5451430c@mail.domain.com> Queued mail for delivery

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