2

I have a Postfix SMTP server running at home which can't send or receive mails because of an ISP restriction. (no incoming port 25, nor outgoing)
I have a VPS with a public IP that I want to use to relay my home mails to the internet.

It should go like this:
receiving mail: Internet > VPS Relay > Homeserver
sending mail: Homeserver > VPS Relay > Internet

I managed to succesfully setup an outgoing postfix SMTP relay which works. The problem now is receiving mails: if I tell the relay to send incoming mails to my home server it works, but it also sends all outgoing mail back to my home server (which sends it back to the relay which sends it back to my home, ...)

I tried to use a SSH tunnel to forward incoming mails on my VPS to my home server, which worked, but also made it an open relay. (The requests came from localhost so everything was allowed)

The only thing I need to know is how to tell postfix to send incoming mails to my home server and outgoing to the internet, but I couldn't manage to find it.

Thanks for taking a look!

Home server relevant config: postconf -n

myhostname = [*homeservers public dns name*] mynetworks = 127.0.0.0/8, [*my public relay's IP*]/32 mynetworks_style = subnet myorigin = $myhostname relay_domains = $mydestination relayhost = [*my public relay's domain name*]:587

VPS server relevant config: postconf -n mydestination = localhost myhostname = [*VPS public dns name*] mynetworks = 127.0.0.0/8, [*home server public ip*]/32 mynetworks_style = subnet relay_domains = soft_bounce = yes transport_maps = hash:/etc/postfix/transport

Improve this question

2 Answers 2

Reset to default
1

The issue is that you have not set "mydestination" so it's defaulting to the value of my hostname, rather then the domain name(s) you are trying to receive mail for, and rejecting other email as not local.

Improve this answer
6
  • Should I set mydestination on my VPS then? My relay does relay mails, the only problem is that outgoing mails are also relayed back to the home server, which sends it back to my VPS etc..
    – cyllos
    Commented Nov 24, 2018 at 18:09
  • No, you should set it on your home server, as this is the server that needs to locally process email.
    – davidgo
    Commented Nov 24, 2018 at 18:15
  • Thanks for helping out, but setting this doesn't make a difference. I can either receive mails but not send them, or send mails but not recieve, depending on wether my relay sends mail to my home server or not. If I enable forwarding mails to my home server everything goes there, not only incoming mails but also the outgoing.
    – cyllos
    Commented Nov 24, 2018 at 18:19
  • What does /etc/postfix/transport contain and what are the timestamps on /etc/transport and /etc/transport.db ?
    – davidgo
    Commented Nov 24, 2018 at 23:55
  • It contains * smtp:[homeserver ip]:587
    – cyllos
    Commented Nov 25, 2018 at 10:15
0

I found a solution!

For those wondering: I added a second postfix server on the same host and used one for receiving and one for sending mail.

Improve this answer
8
  • Well done on getting a solution - but you really don't need (or in my opinion want) 2 servers on 1 system.
    – davidgo
    Commented Nov 25, 2018 at 17:53
  • I know it is not the best solution, but right now this is good enough. If anybody knows a better solution please let me know
    – cyllos
    Commented Nov 26, 2018 at 12:20
  • Fix your transport table as above!
    – davidgo
    Commented Nov 26, 2018 at 17:25
  • Thanks for helping out. Setting this on the home server does not make any difference, as my VPS still thinks it should forward all mail to my home server, even outgoing mail.
    – cyllos
    Commented Nov 27, 2018 at 16:15
  • Can you show the timestamps of the transport and transport.db file - ie ? did you rebuild the .dB file?
    – davidgo
    Commented Nov 27, 2018 at 18:24

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .