SMTP Trusted Relay

We have two seperate LANs in the same office. Each LAN has its own cable modem thru the ISP and own unique static IP. LAN 1 has an Exchange 2003 server. LAN 2 has no Exchange server. LAN 2 is running a SQL application that does sent email notifications

We want to setup a trusted relay so that LAN2 is able to send email thru the Exchange server on LAN1.

Can someone please advise on the necessary steps to create the trusted relay?
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Here you go Follow these Instructions and all will be fine:,289483,sid43_gci1061687,00.html

Key is add these Servers to permitted relay list.
This is also a good Resource:

bnrtechAuthor Commented:

Thanks for the quick response. I did review the links you sent. Option 1 noted in the second link you noted (,289483,sid43_gci1061687,00.html) sounds like a good fit. However, where I am getting lost is what data I need to add when I update setup the relay.

In other words, LAN 2 does not have a qualified domain name (it is literally consists of one box running a SQL app). I would guess that on the Exchange server when I update the SMTP connector I would (somewhere) enter the IP address for LAN2, but I am do not see any location to enter an IP address. Only thing I see is to enter a domain name, but that is not applicable here.

What am I missing?

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Go to SMTP Connector Settings and Under Connections You can add the IP address.


Here are the steps:

  • Right-click the virtual SMTP server where you want to prevent mail relay, and then click Properties. Click the Access tab, and then click Relay.
  • By default, open relay is blocked. The default settings are as follows:
    The Only the list below check box is selected.

    The Allow all computers which successfully authenticate to relay, regardless of the list above check box is selected.
    If you must permit a single computer, a group of computers, or a domain to relay through the server, click Add. In the Computer dialog box, click the appropriate selection for the computers you want to relay through the server. Then, type the required information.

    Note Enabling access by IP address or by domain name is helpful for users who do not authenticate with the Exchange computer. In the Relay Restrictions dialog box, click OK. Click Apply, and then click OK in the Default SMTP Virtual Server Properties dialog box.

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Here is the Link to the KB Artcle:

Can you do a Test from your SQL server lan:

Telnet "yourMailServer" 25

If you are successfully able to connect to your mail server then you don't even need to change anything on your exchange server.
Here is a link that will show you how to do the test:

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