Newbie question, setting up postfix

I'd be grateful for anyone's help on this.

I'm trying to learn UNIX, I find I learn better by throwing myself in
to a real world task, so I thought I'd start out by setting up a mail
server.

I'm using the guide at http://flakshack.com/anti-spam/

There is an instruction at the bottom of this page:

http://flakshack.com/anti-spam/wiki/...guring+OpenBSD

It says:

Add the following line to the bottom of the [hosts] file:
10.2.1.50 mta1.domain.com mta1


Do they mean this literally (ie type in that exact sequence of
characters) or should I replace "domain.com" with my real domain name
and "10.2.1.50" with my server's IP address?

[...]
> Do they mean this literally (ie type in that exact sequence of
> characters)
no

> or should I replace "domain.com" with my real domain name
> and "10.2.1.50" with my server's IP address?

exactly! Anything else wouldn't make sense.