POSTFIX behind a firewall (NAT)

[garr...@outlook.com]

Postfix does not answer any connection attempts form outside my network, but the request do come as I validated in "tcpdump port 25".

External IP = e.e.e.e
Internal IP = 192.168.100.40

Firewall has NAT rule for IMAPS, POP3S, HTTPS and SMTP
Yes I can connect to IMAPS, POP3S and HTTPS from the outside fine and based on the logs, it shows the correct from IP.


Using tcpdump, I see the packets coming in 192.168.100.40 for port 25.

If I test using telnet 25 from external, I see the packets coming in, but no answer nor is anything logged in syslog or mail.log . I set smtp -V in master.cf to get verbose logs.

If I test using telnet 25 from internal (192.168.100.21) , I see the packets coming in, and postfix answers. I am able to send a test message to one of the mailboxes and everything works.

postfix is listening on all interfaces:
tcp 0 0 0.0.0.0:smtp 0.0.0.0:* LISTEN 1201/master

Anyone ever see something like this?

[Luuk]

On 25-9-2018 21:37, garr...@outlook.com wrote:
...

> Internal IP = 192.168.100.40
...

> If I test using telnet 25 from internal (192.168.100.21) , I see the packets coming in, and postfix answers.

what is your internal ip? is it .40 or is it .21 ?? od do you have more
than 1 mailserver?

> I am able to send a test message to one of the mailboxes and everything works.

If everything works, what is your problem??

> Anyone ever see something like this?
>
>

Try to find out what your problem is, than find the correct place to ask
a question about how to solve your problem.