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Deciphering the least cost routing algorithm

Do you have mail routing anomalies, or just want to be sure that your email is set to route to where you expect it to be?

Do you have mail routing anomalies, or just want to be SURE that your email is set to route to where you expect it to be routed?

Before you attempt any troubleshooting, I would recommend a sound understanding of the Notes Router. Try researching in Rob Kirkland's excellent reference book, Domino System Administration.

There are a couple of non-documented notes.ini settings (R4.x and up) that might help.

(Always remember that Lotus uses the many HUNDREDS of undocumented Notes.INI parameters for their own internal validation, so they are not covered by any warranties or support. I would recommend NOT using a production server; use an isolated test box for your server, with an up-to-date Domino Directory and the server's id file. Then you will see the router try to build its table without jeopardizing any corporate systems or data.)

Remember all the warnings about messing with the Notes.INI -- make a backup, use a config document (or as a last resort tinker directly with the Notes.INI file). Should you fail, all knowledge of this conversation will be denied and you will be left culpable. You mission, should you choose to accept it, is to decrypt what exactly your server thinks is the least cost route.

 Add: DEBUGROUTER=3 to your server's notes.ini file and you will see the server dynamically calculate the routes. You can decrement the value to reduce the volume of reporting. (0=No details 1=itemised step though ALL connection docs in the DD, including type and cost 2=More info 3=Verbose)


 Add: Console_LogLevel=4

to your server's notes.ini file, and then any console opened on this server will give full trace information

 (0 = none 1 = errors 2 = Summary (default) 3 = Detailed progress info 4 = Full Trace)


 Log_MailRouting=40 (0 - Defaults to 20 10 - Only shows errors, warning, and major events 20 - Same as 10 but successful deliveries and transfers are also logged 30 - Adds thread information 40 - Adds transfer messages, message queues, and full document information


to record details of lookups in address books.

Bear in mind that the "Dynamic" recalculation is slightly misleading. The Notes Router calculates the Least Cost Route. If the next server cannot be contacted, then the Router increments the cost of this route by one, and recalculates to check the Least Cost Route, again -- but ONLY ONCE. The cost will be reset after the period of time specified in the appropriate Configuration document, the Dynamic Cost Reset Interval Control, located under Router/ SMTP, Advanced (which has a default of 30 mins).

Finally, after you have finished troubleshooting, don't forget to disable/remove these settings -- ESPECIALLY IF YOU HAVE UPDATED A PRODUCTION SERVER, or the log will coninue to be flooded with (unnecessary) minutiae ...

buona fortuna

Dig Deeper on Domino Resources - Part 3

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