Postfix , cant connect through telnet

Solution 1:

Your postfix is configured to accept incoming tcp (smtp) connections only on loopback/localhost interface. It makes sense as default on most "single user" computers.

Change inet_interfaces configuration setting to change it.

Your master.cf file:

# The inet_interfaces parameter specifies the network interface
# addresses that this mail system receives mail on.  By default,
# the software claims all active interfaces on the machine. The
# parameter also controls delivery of mail to user@[ip.address].
#
# See also the proxy_interfaces parameter, for network addresses that
# are forwarded to us via a proxy or network address translator.
#
# Note: you need to stop/start Postfix when this parameter changes.
#
#inet_interfaces = all
#inet_interfaces = $myhostname
#inet_interfaces = $myhostname, localhost
inet_interfaces = localhost