From the draft 1.8b release notes: - (non-VM) New SMTP_RESET_EVERY configuration option: this option directs LISTSERV to drop its outbound SMTP connections at regular intervals. The value of the keyword is the number of minutes between each forced timeout. This option may be useful if you are using sendmail as a mail delivery agent. On an active system, there may be enough traffic to keep the connections active 24 hours a day. The size of the sendmail process driving the connection appears to grow with time, with observed values of a dozen megabytes after a week of activity, presumably due to storage fragmentation. Since this is the process from which all the delivery subprocesses are forked, the sendmail processes get bigger with time, and some customers have reported increased swap rates as a result. Resetting the connection regularly (say every 8h) prevents this phenomenon. I will update this paragraph with your figures :-) Eric