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.

yes. can your cell phone handle authentication?

web mail?

Thank you for the replies, I will look into a SASL authentication.