We are running Postfix on a SuSE 11 SP 1 host, using ClamAV and ClamSMTP to scan mail messages. Mail delivery and reception works great. Had some issues with duplicate mail messages that we fixed with a global procmailrc file. The one remaining problem we have is that when we send mail to a relatively large mail alias (441 addresses), the system will process through 284 addresses and flag the message as unsent and put it back in the queue with the error message "mail transport unavailable". Unfortunately, the system is on a separate network so I can't easily post configuration files, but if someone knows where I could start looking, I can post specific configuration items.
For example, I have tried increasing the number of open files in the /etc/security/limits.conf (up to 32k), I have increased several values in the /etc/clamd.conf file to see if I was running into some resource limitation (increased MaxThreads, StreamMaxLength, and MaxQueue); I have done the same for clamsmtpd.conf (increased MaxConnections to 1023; it wouldn't let me set it to 1024). Within master.cf I have set the post-processing smtpd service option smtpd_client_connection_count_limit and smtpd_client_connection_rate_limit to 0 to disable them. It seems to me that somewhere I am running into a resource limit, but I can not find any trace of what or where. Thanks, Geoff
