Hi,

I am trying to setup a new domain to accept mail for the primary domain which is located on another machine.

me.com (same as www.me.com) is on another server somewhere else in the world.

I setup mail.me.com at RackShack (CPANEL/RHE3). It is on a dedicated IP. All setup was done via CPANEL, i.e. a standard web hosting account.

I want mail.me.com to accept all mail for me.com ( me.com does not have anti-spam tools and never will ).

I know I have to setup a DNS MX record for me.com to point to mail.me.com.

I am guessing that I also need to add me.com to /etc/localdomains?

But it seems like something is missing? How does EXIM know that me.com maps to mail.me.com? Does it do a DNS MX lookup to see who handles it or is there some other config parameter that does the mapping? For example, if I have 100 other domains on the same box where mail.me.com is, how does EXIM know which of the 100 domains is supposed to accept the mail?

All an MX record does is point your domains email domain (i.e. me.com) to your server. Email is then sent by SMTP servers to that IP address, where Exim is listening. Exim then checks in it's local relay database (/etc/localdomains) for the domain specified in the RCPT SMTP mail command and if found accepts the email for local delivery, otherwise it rejects it.

There are two ways that you could setup what you want. The simplest would be to simply park me.com to an existing cPanel account and change the FQDN that the MX record points to (mail.me.com) to the IP address used by that account. You can then add a Default Address and POP3 accounts for that domain within the cPanel account.

If you would rather keep it separate from any other account, you could simply create a new one in WHM for me.com, but make sure you correct any DNS changes so that only mail.me.com points to that server.