How do I set up an inbound message router (IMR) or outbound message router (OMR) in a firewall's DMZ?

Issue

How do I set up an inbound message router (IMR) or outbound message router (OMR) in a firewall's DMZ?

Solution

It is possible to set up an IMR/OMR system on the part of a network that is outside the firewall. All inbound email can be passed into an exchange IMR, and the Message Server or RazorGate appliance is then used as an OMR to the Internet.

Note the following difficulties:

• Since the Message Server or RazorGate appliance is both an IMR and an OMR, the SMTP OMR setting cannot be used to route both inbound and outbound mail.
• The appliance does not have access to the internal DNS of the company, so host names cannot be used.

The appliance must have the LDAP routing license, and the LDIF flatfile to provide the routing information. The LDIF is set up to route all mail to customer.com and a hard-coded IP address.

To do this, enter the following commands:

License Apply Ldaprouting

Maildom Add customer.com

Smtp Set Laprouting On

Ldap Set Ldif {...}

... ldif ...

The LDIF should look like:

dn: dc=customer,dc=com

mail: @customer.com

mailhost: 10.0.1.2

where 10.0.1.2 is the IP address of the internal IMR.