Calculating the max. clients by worker_connections

[mikiso]

Hi, 

Regarding max clients , I understand it's normal to have 4 in reverse
proxy
since  browser  uses 2 connections in HTTP 1.1.
How about mail reverse proxy?
It seems POP command from telnet client uses 4 also, although I couldn't
find 
POP3 uses more than 1 connection in RFC 1939.

Regards,
Soichiro

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,171776,217904#msg-217904