I've looked around at my MT configuration and I don't have any throttling enabled. That and the fact that it's a 403 error indicates that it is being done by the webserver.
Trackback ping throttling is always enabled in MT, even if you don't see any settings that would appear to enable it.
Any dynamic script (such as .php and .cgi scripts) can return an HTTP error on its own (such as a 403 error). In the case of a trackback ping that is throttled, it is MT that returns the "403 Throttled" error, not the web server.
What aspect of the webserver configuration generates a 403: Throttled error?
As noted above, it is not the web server that is returning the "403 Throttled" error, it is MT itself.
Is this configuration on my server, my weblog, the mt-tb script?
The configuration settings that control MT's trackback ping throttling are in your mt-config.cgi / mt.cfg file. There are three settings that affect trackback ping throttling:OneHourMaxPings
- The maximum number of pings that a weblog can receive in one hour. If this setting is not present, MT uses a default of 10 for this setting. OneDayMaxPings
- The maximum number of pings that a weblog can receive in one "day" (with one "day" being determined by the ThrottleSeconds setting below). If this setting is not present, MT uses a default of 50 for this setting.ThrottleSeconds
- This setting is the minimum number of seconds between comments from a single IP address. MT also uses this setting when deciding whether to throttle trackback pings with the OneDayMaxPings setting, with one "day" being (4000 * ThrottleSeconds -1) seconds. If this setting is not present, MT uses a default of 20 for this setting. With the default of 20 seconds, one "day" for the OneDayMaxPings setting is a little over 22 hours (80,000 seconds).
Is the proximate cause traffic at my website or could some other MT weblog be loading the server?
Yes, the proximate cause would the combination of traffic at your web site and whatever settings MT is using for trackback ping throttling. Another MT weblog would not be able to cause your site to throttle trackback pings.
My mt-tb script is in an scgi-bin directory, is that an issue?
If I rename the script, would that avoid throttling? Or would that be cheating?
Having MT in an scgi-bin directory would not affect trackback ping throttling.
Renaming the script would not be "cheating", but it would have no effect whatsoever on MT's throttling of trackback pings.
What you would need to know is the pattern of trackback pings being sent, and what MT is using for the three configuration settings above. Assuming the default for all three settings, even if you receive "only" 20 trackback pings in a single day, receiving one ping per hour for 20 consecutive hours would not trigger throttling by MT. But receiving all 20 within a single hour would cause the last 10 to be throttled, as this would exceed the OneHourMaxPings setting of 10.
The OneHourMaxPings and OneDayMaxPings settings are not present in a default mt-config.cgi / mt.cfg file. You can add them to your configuration file if you would like to use settings other than the default. Example:
ThrottleSeconds should be present in your config file, but commented out. If you wish to alter this setting, you would need to uncomment it (remove the "#" from the beginning of the line).
Hope this helps...