Environment (all servers running Debian etch w exim4 and latest patches applied). Both Linux-Servers are running FWBuilder iptable firewalls.
Scenario sending a mail from the WXP PC: * WindowsXP-PC w Thunderbird (eMail source) -> MailServer1 (gateway, smart router, connected via DSL Router) -> MailsServer2 (relay, outgoing eMail) sending emails to the final destination. Anything works fine until large eMails (or eMail w large attachments / approx > 1MB) are sent. Whenever large email are sent, the connection once is broken and the sending host (Server1) retries sending the emails on next queue-run. >From the exim log of Server1: "R=smart_route T=remote_smtp defer (-46): SMTP error from remote mail server after end of data: host xx.xx.xx.xx [xx.xx.xx.xx]: 421 adomain.eu SMTP incoming data timeout - closing connection" I did some investigation a few weeks ago and found out that after a while fragmented packets are sent over the Internet line. I tried some "optimized" MTU settings but could not solve the problem. I do not think it's a problem with the MTU. Regardless of the problems sending large mail from Server1 to the internet, receiving large eMails is not a problem. Any help appreciated. -- ## List details at http://lists.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
