Hi all, I have got reports about lost mail(not received, im the receiver not the sender) recently and trying to find out whats going on seems to be beyond me.
Basically a lot of email is lost with "timeout after DATA" For example: timeout after DATA (0 bytes) from mail.securepay.com.au[203.89.212.166] . Supposedly the problem here is that the sending machine has got a firewall in front of it thats blocking ICMP MUST FRAGMENT. I somewhat could verify this by trying to ping those machines and indeed pinging them does not work. On the Postfix website it suggests lowering MTU, so I lowered it from 1500 to 1000, but this did not improve the situation at all. Some suggest disabling PIPELINING, so i did that but it didnt work either. I took a tcpdump of one of these and attached it to this email. (daria is the name of the mail server) The system is running DragonFly 2.0.0 with ETHER_INPUT_CHAIN and ETHER_INPUT2 enabled. Just a note about my setup: The server is running behind a Cisco ADSL Router that connects to a Cisco switch and the server connects to the switch. Any Postfix gurus here that could help me figure this problem out? Thanks, Petr
postfix_dump.tgz
Description: application/tgz
