The program I used for this comes with LSMTP, it reads the accounting files (you need to enable full accounting). It could probably be modified to work with sendmail logs, or perhaps one could write a program that reads a sendmail log and outputs a file in the same format as LSMTP accounting records (I can send you the specs). But I know that some people have written similar utilities that work directly on sendmail logs. The metrics may not be the same but you will get an idea of your round trip times. Eric