I'm not being allowed to add relayers for exim

[hariskhan]

Hello,

I'v tried putting in host-IP email-address in /etc/relayhostsusers and host-IP in /etc/relayhosts, so exim would allow me to configure who relays through this server, but everytime as soon as I save changes and quit the editor the above two mentioned files get over-written.

I can only conclude that the above mentioned two files are constantly getting over-written to prevent the system from hosting invalid or malicious relayers accessing our server.

How can I safely add relayers;

1) host IPs
2) email addresses

such that WHM/cpanel or whatever it is that is over-writing or securing these files, doesn't over-write my settings

 

[brianoz]

You safely add relayers by using SMTP Authentication, where their mail client gives a password to allow it to relay, or by using POP-before-SMTP which is where successful authentication for POP allows SMTP from the same IP address for a while.

Putting fixed IP addresses into those files isn't the way to go, they're rebuilt regularly to assist with POP-before-SMTP detection. Do you really need to do it via IP? I'd say that's fraught with danger!