Configure open relay on specific port

[Patric Falinder]

Hi,

I need to configure Postfix to be an open relay on a specific port, lets 
say 3326. I already have Postfix configured like a normal mailserver 
that requires authentication etc. but I need it to not ask for 
authentication on port 3326. How do I do this?

I know this isn't safe but this port wont be open for the internet, just 
specific IP's that I specify on my router, so I wont be a target for 
spammers.

I already have port 3325 open just like port 25, I did that by just 
adding this to /etc/services:
smtp2           3325/tcp

and in /etc/postfix/master.cf:
smtp2      inet  n       -       -       -       -       smtpd

So I can do the same for port 3326 but I don't know how to disable the 
authentication part. How can I do this?

Thanks,
-Patric