Kolab 3.1 postfix relay access denied

[Tomas Kucera]

Hi there,

I would like to ask for a help. I am not at all proficient in postfix. I got to a point where it seems like a lot of things work as expected. The current thing I am fighting is the following:

- CentOS 6.5
- Kolab 3.1 (tried 3.2 but the multidomain setup just did not work)
- multidomain setup
- from Roundcube everything works fine
- from external client (in my case Mail on Mac) when sending an email to a domain that is outside of the domains under control of Kolab / postfix I get Relay access denied.

I suppose that it is correct with the default setting but I just cannot figure out how to configure the postfix in a way that it will accept authenticated users and will allow them to send the emails everywhere.

I went through the documentation of postfix and tried some of the options for smtpd_xxx_restrictions, but did not get it to work.

So, please, please, help me!!!

A bonus would be to give some hints on potential security threats.

Thanks in advance!

Kind Regards,
Tom.