I am using postfix for outgoing mails (collection from machines on 192.168.1.0/24 and forwarding to my ISP's mail machine) and I have trouble accessing postfix for sending mails. The machine I use for postfix is a debian system, kernel 2.6.32, squeeze (it's also my squid proxy).
There are probably many reasons why postfix might not work as desired, but I'd like to rule out settings in hosts.allow or hosts.deny. Thus, my question:
Does postfix have its own way to listen for mails (in the same way, for example, squid has for listening on 192.168.1.0/24, port 3128 or 8080 as configured in squid's own config files), or do I have to enable something system-wide, e.g. by modifying hosts.allow or hosts.deny?
Some more details along my main question:
ping or ssh to the postfix machine run just fine.
Squid, on the same machine, listens as it should; telnet to the http ports 3128 or 8080 is o.k.:
$ telnet 192.168.1.1 3128
Connected to 192.168.1.1.
Also, squid runs just fine as a proxy.
Telnet to port 25 is not successful:
$ telnet 192.168.1.1 25
telnet: Unable to connect to remote host: Connection refused
DNS lookup seems to be o.k., too: For instance, both squid and apt-get find everything they need.
Am I correct when I assume that postfix itself will start listening on port 25 once its main.cf is set up correctly and hosts.allow/.deny have nothing to do with it?