As I´ve been told this is an ancient way of authentication.
The client connects to the server, the server then initiates a TCP
connection to port 113 of the client, there should be the identd
listening that sends back some lines of text identifying and possibly
authentifying the client to the server. Then the actual connection
carries on.
Not only MTAs do this. telnet, ftp, pop3, and several other daemons
behave like this as well.
I think it is somewhat obsolete, you can cut it off by adding
"rfc1413_query_timeout = 0s" to exim.conf.
Tobias
robert rotman wrote:
> why do MTA's make a tcp connetion to the auth-port (113) to the host
> starting an smtp connection?
> is this necessary?
