Cannot Send Emails Within Our Network

Posted on 2005-03-08
Medium Priority
Last Modified: 2012-05-05
We have a simple Windows Server 2003 Domain with 5 users.  We are behind a SonicWall firewall and a WorkGroup Switch.  We use a third-party ISP for basic POP3 email within Outlook Express.

The issue is that we cannot send emails to other users within the network but we can send out and receive from the outside.  The sender receives no message back and the receiver receives nothing.  Users cannot even send/receive emails to themselves.

Any suggestions?
Question by:btmtech
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Expert Comment

ID: 13491124
Do you have the reply email address specified within the accounts setup? If so try to remove that email address from there.

Expert Comment

ID: 13492446
I am making a big assumption here, so if the answer to the "IF question on the next line is "no" then disregard.  Otherwise:

IF your internal WIn 2003 domain name is the same as your "public" domain name, you probably need to modify DNS on the internal server.

Add a host (A) and MX record to DNS on the 2003 domain controller (or DNS server) that says:

A record for host name "mail.yourdomain.com" is at IP address "IP_of_the_ISP_mail_server_hosting_your_domain"

MX Record that says MX for "yourdomain.com" is "mail.yourdomain.com"

The IP address you want to use for the A record of "mail.yourdomain.com" can be found by doing (from outside your network):


(this should return the name of your primary "public" MX (mail exchanger).  Don't close NSLOOKUP yet, but now:

[MAIL.YOURDOMAIN.COM] (or whatever result was returned on the MX query above).
This will tell you the public address to use for the A record you create in DNS on your server in the early step of my post.


Author Comment

ID: 13499569
The issue resulted from the ISP giving us an ip address that was blacklisted!!  Thank You for Your Help!!

Accepted Solution

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ID: 14410267
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