XCON: Configuring an X.400 Connector with Microsoft Proxy 2.0 (263046)

SUMMARY

The following diagram and list of Internet protocol (IP) addresses is an example of the relationship between Exchange Server computers and a proxy server:

Server A to Proxy Server to Server B

   Server A's IP address:              172.16.1.10
   Proxy Server's internal IP address: 172.16.1.11
   Proxy Server's external IP address: 192.168.1.1
   Server B's IP address:              192.168.1.2

For the Exchange Server computers to communicate through Microsoft Proxy 2.0 by means of X.400 Connectors, the proxy server must allow traffic in both directions over Transmission Control Protocol (TCP) port 102.

The Request for Comments (RFC) standard for X.400 requires a reverse Domain Name System (DNS) lookup on the reply address. This requires a second X.400 Connector to be added. Otherwise, the ephemeral port will not know where to pass the new packet.

MORE INFORMATION

Proxy

The proxy server accepts a packet from an Exchange Server computer, encapsulates the packet into a new TCP/IP packet, and then sends this new packet to the destination Exchange Server computer. This new packet appears to have been sent by the proxy instead of the sending Exchange Server computer. The proxy server behaves in this manner because of the rules that the system administrator has configured within the proxy server.

In an environment where the proxy server is configured to behave in this manner, there must be an X.400 Connector that is configured to connect to the proxy server in addition to the one configured to the destination Exchange Server computer. Using the IP addresses in the diagram in the "Symptoms" section, the process is as follows:

The X.400 Connector that is installed on the first Exchange Server computer (Server A) connects to the network interface of the second Exchange Server computer (Server B).

NOTE: Type the IP address of 192.168.1.2 on the Stack tab in the properties for the first X.400 Connector for Server A.
You must add an additional X.400 connector that connects to the internal network interface of the proxy server.

NOTE: Type the IP address of 172.16.1.11 on the Stack tab in the properties for the added X.400 Connector for Server A. Set the schedule on this secondary connector to "Never".
Similarly, the X.400 Connector installed on Server B connects to the network interface of the first Server A.

NOTE: In the preceding example, type the IP address of 172.16.1.10 on the Stack tab in the properties for the X.400 Connector on Server B.