> On 29 Dec 2020, at 12:58, Wolfgang Paul Rauchholz <wp.rauchh...@gmail.com>
> wrote:
>
> The server is listening on port 25, 587 and 465
> netstat -plutn | grep 25 and 587
> tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN
> 28704/master
> tcp 0 0 127.0.0.1:587 0.0.0.0:* LISTEN
> 21435/smtpd
>
> I can send mails to my gmail account. But when responding to this mail I get
> nothing back
That’s to be expected. You seem to have configured postfix to only listen on
port 25 for the loopback interface (127.0.0.1). If postfix isn’t listening on
an IP address that’s reachable from the Internet, it’s never going to receive
any email from the Internet. Check inet_interfaces in main.cf and post the
output of postconf if you need further help.
postfix should probably be listening on that 10.5.2.1 interface (as well as
127.0.0.1). But there will be even more to do. 10.5.2.1 is a private IP address
that isn’t routed on the Internet. See RC1918. So that isn’t reachable either.
Presumably your DSL or cable box is doing network or port address translation
to map its real IP address on to 10.5.2.1, the internal one you’ve used on your
home network. You’ll need to confirm that address translation is working
correctly for both inbound and outbound packets.
You’ll also need to configure the DNS for your domain name(s) to have MX
records that ultimately map to that public IP address. If not, the world won’t
know how to deliver email to you. ie in the zone file for your-domain.com have
entries like:
your-domain.com. IN MX 20 foo.your-domain.com.
foo.your-domain.com. IN A public-ip-address-goes-here
On your internal network, you’ll need to configure mail clients to connect to
port 25 on 10.5.2.1 when they send email. Or use the loopback interface if the
clients run on the same box that’s running postfix. You could do this with a
split DNS configuration - two versions of your-domain.com, one for the Internet
and one for your internal net. However based on your questions here, that
requires a lot more DNS expertise than you appear to have. Questions about that
belong on a DNS forum and not the postfix mailing list.
BTW Your test connections to 10.5.2.1:imap work because IIRC dovecot listens on
all available network interfaces by default. postfix has to be told which
interfaces to listen on port 25 for incoming email.
