Hey,
I registered on the SMTP::mime_end_entity event to inspect some SMTP traffic.
I am printing the ‘c$smtp$uid’ to a log file and I noticed that once in a while the UID repeats itself.
I started debugging this and I noticed that a certain email X that was sent 5 times to 5 different recipient had the same UID.
I was looking at calculate_unique_id() that generates this UID and I cannot understand why this happens.
Why all those specific emails have the same UID?
Thanks,
Dave
I registered on the SMTP::mime_end_entity event to inspect some SMTP traffic.
I am printing the 'c$smtp$uid' to a log file and I noticed that once in a while the UID repeats itself.
Hopefully you're logging more than that since the uid value by itself it pretty useless. 
Why all those specific emails have the same UID?
That would mean that all of those emails were sent over the same TCP connection. UID values are a fairly arbitrary representation for a single connection. For instance, if two hosts establish a connection then shut it down and then establish a new connection using the exact same ports there would be a new UID value. It's primarily used as a very easy method of joining various log files together without having to match on the 2 IP addresses and 2 ports with the added benefit of distinguishing between connections reusing ports.
.Seth