What does the log message no immediate delivery: more than 10 messages received in one connection mean?
A0049: A remote MTA sent a number of messages in a single SMTP session. Exim limits the number of immediate delivery processes it creates as a result of a single SMTP connection, in order to avoid creating a zillion processes on systems that can have many incoming connections. If you are dialing in to collect mail from your ISP, you should probably set smtp_accept_queue_per_connection to some number larger than 10, or arrange to start a queue runner for local delivery (using -ql) immediately after collecting the mail. Q0050: I am getting complaints from a customer who uses my Exim server for relaying that they are being blocked with a Too many connections error. A0050: See smtp_accept_max, smep_accept_max_per_host and smtp_accept_reserve. Q0051: When I try exim -bf to test a system filter, I received the following error message: Filter error: unavailable filtering command “fail” near line 8 of filter file. A0051: Use the -bF option to test system filters. This gives you access to the f
