Since mid-2005, we are starting to observe a large latency in the java.net e-mail delivery. For example, when someone commits a change in CVS, the delivery of the change notification e-mail often gets delayed. When you post to a mailing list, the distribution of that e-mail gets delayed, similarly.

So I started monitoring this delay, in an attempt to better understand the problem, and to reduce the impact it causes to our projects.

My monitoring system sends out an e-mail from kohsuke.sfbay inside Sun firewall. The e-mail goes through a Sun mail server, then java.net mail server, comes back to a Sun mail server, then finally to kohsuke.sfbay itself. The 'latency' measured is the time it takes for an e-mail to complete this whole journey. This happens every 15 minutes.

Therefore, it is not the exact delay in java.net; it includes all the latencies in Sun mail servers. (Note that in our experience Sun mail servers have minimal latency, usually in the order of seconds.)

I hope this works as a kind of "weather forecast" for those of us who are affected by this. I've heard from Collab.net that they are working on addressing this issue.