Postfix: any way to prevent spam with mynetworks open?
Hello and Happy mother's day.
I rent an ubuntu VPS, hosted out in CA somewhere. I want to use this computer as the mail server for my domain (postfix: SMTP and courier: IMAP). It is tricky because this computer is NOT at the 'top' of my network.
Issues arise with the 'mynetworks' parameter of the postfix configuration.
The mail system works fine, however I believe I am exposed to spammers. In order for the mail server to act as a relay server from my mobile clients (my cell phone), I needed to open up the mynetworks parameter to:
mynetworks = 0.0.0.0/256
Unfortunatley, the other mobile clients do NOT have static IPs, so I cannot append their address to this parameter.
I understand that this is highly insecure. I am wondering what other appraoches I can take to opening up relay access to my mobile clients.
Will an implementation of SASL 'lockdown' SMTP?
Thank you in advance.