SMTP - Disable Auth and allow Relay via Whitelist_Senders

Greetings all.....

After spending days to find out how to setup my cPanel DNSONLY server [WHM 11.48.1 (build 3)] to act as a relay server for my selected clients, without having to create an email account locally on the server, solely an relay SMTP server, as there are some ISP's that have issues with their SMTP server, so I am offering this as a service to my clients only.....So I am trying to setup my SMTP server to either:

[Legend:]
whitelisted senders (/etc/exim/whitelist_sender <= has the clients EMAIL addresses listed in it)

(a) disable it's authentication requirement and allow relays only for whitelisted senders, or
(b) allow whitelisted_senders to relay emails without authentication, and if not whitelisted, then needs to authenticate before sending...

ie.

Client sends email
||
SMTP server
||
||
|------> Email address Whitelisted?
||
||-----NO
| |
| |
| User Authenticated itself?
| | |
| | |--NO ==> REJECT
| |
|------Yes ====> Receive and relay (Send) email

Above is ideally what I want to have....

Now many have commented the need to modify the section :
"require verify = sender" ,

but in this version of cpanel there is none...

I have attached the exim.conf file for your review...

Your assistance in this will be most appreciated.

 

Thanks for your reply.

Please note....I don't intend for this server to HOST email, not any other means of hosting (websites, MySQL, etc), but to solely act as a SMTP Relay service....

This server comes equip with a fully functional SMTP server, Exim, and I have tested it in my environment which shows to be very efficient, just I have the following to major issues.......

1) I can not turn off the authentication requirement in the Exim for I can not find it in the exim.conf
2) leaving the authentication method enabled (or disabled), I can not get the WHITELIST_SENDERS function to work as this version of WHM (v11) does not have the section "require verify = sender/callout" as per 90% of the websites (eg. esolutions.net/faq/pdf.php?cat=6&id=94&artlang=en )

All I ask, as you guys are more knowledgeable on EXIM and cPanel, is to just tell me WHERE to either:
1) disable the password authentication and enable WHITELIST_SENDERS, or
2) enable WHITELIST_SENDERS and have is BYPASS the authentication requirement......

Simple...... but I have spent HOURS and HOURS trying and trying to get it to work... just can not find it.....

PLEASE help me... PLEASE!!!

 

Nope... as a Relay server.

Clients send an email to the smtp relay... if their email address is whitelisted then no further authentication is required, if not... then authentication is required, if failed then drop connection. .. simple...

After spending days on this issue with no assistance from cPanel Support i have final managed to get it to work and it is not to the advice of whitelist_senders for exim on google and other sites/forums...

But rather to setting up addtional ports with condition rules in it...