I was just asked the question if it is possible to define different IP addresses on the same machine for inbound and outbound SMTP traffic for a Domino server.

The answer is: No, that is not possible. Although you can define a network port which should be used for SMTP traffic by setting the NOTES.INI variable "SMTPNotesPort=portname" this port would then be used for both incoming and outgoing SMTP traffic.

Lotus Domino: Different IP Addresses for Inbound and Outbound SMTP Traffic
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9 thoughts on “Lotus Domino: Different IP Addresses for Inbound and Outbound SMTP Traffic

  • 22.02.2008 at 16:20

    I believe you are incorrect in your thoughts.
    You can have multiple NICs ande assign each an IP address and a connection document for each route for in and outtraffic.
    Inbound comes in obviously via mx records and to the server to handle the task.
    Outbound goes through card #2.
    What is the problem?

    A similar setup I have used for failover routing by adjusting routing tables and backup card priorities.

  • 22.02.2008 at 17:07

    Hm, not sure if I got it ... If you want to use one NIC for inbound SMTP traffic nd one NIC for outbound SMTP traffic then Domino would have to listen to both NICs (bot IP addresses) on port 25 (SMTP), right?

    And I think exactly that is not possible. Domino onlylistens to one IP address (the port which is defined first or the port which is defined with the NOTES.INI parameter).

    Maybe you could clarify a little bit more? Thanks!

  • 22.02.2008 at 17:41

    Chris discussed something very similar, with websites added here:

    Domino will listen on incoming on all IPs for port25.
    Outgoing you can specify the connection document for "the internet".
    That connection document may be a sepearet Notes network and/or port addition to your server with the approrpiate ini settings adjusted.
    Think of it like a partition server when it is defined in the notes.ini.
    NIc1=ip #.#.#.#

    Adding the SMTP relay host to the connection document for outbound I would think should resolve it.

    I can't test it right now, not physically near any servers to play with.

  • 22.02.2008 at 18:04

    I referred to KB article 1272519 which says "a Domino SMTP server is designed to use the same NIC for both IB and OB functionalities. The NIC used by SMTP may differ from a NIC used for Notes/Domino functionality (such as clustering); however, SMTP functionalities are not dispersed across more than one NIC.".

    If I understood Chris' post correctly it should be working when creating an Internet Site document for SMTP, right?

    So the above tecnote would be wrong (not very old and valid up to Domino 8).

    Unfortunately I cannot currently test it as I do not have machine with two NICs available.

  • 22.02.2008 at 18:52

    Just did another test with a Domino R7.02FP1 server.

    2 IP addresses bound to the same NIC.

    Created Internet Site Document for SMTP inbound (added both IP addresses which are bound to the NIC), Internet Site document for Web and a Global Web Settings document. Enabled "Load internet configuration from Internet sites documents". Restarted server.

    Result: Domino is still listening on port 25 only to one TCP/IP address: The address bound to the first port in NOTES.INI or the one which I configure with the SMTPNotesPort setting ...

    What else do I have to do to get Domino listen on more than one IP address on port25??

  • 22.02.2008 at 20:47

    With Windows it's certainly possible to have two NICs in the server, each on a different address, and have the server accept incoming mail from either. I've done this frequently with one NIC on the internal private-IP LAN and one on the Internet.
    If the Internet routing is set up properly in Windows then Domino will pick it up. If you want to prevent SMTP from going out a particular NIC then don't assign a gateway address for that NIC.

  • 22.02.2008 at 21:17

    Binding 2 IPS to a NIC is never easy. But the inbound is not the issue, it is the outbound which is what needs to be set.
    If your connection document from the server to the internet is using the ip address for outbound it should be working.
    If I get some time over the weekend will try to test a config for you, but no promises, I still have US corp taxes to finish.

  • 21.08.2008 at 18:45

    Just had this issue on AIX with Domino 8.0.1.



    This will allow inbound SMTP on both ports BUT out will default to TCPIPEXT.

  • 23.09.2008 at 03:57

    i think ur wrong...ehmm


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