[IMail Forum] iMail as a spooler?

[Alist]

        I am considering using iMail as a backup mail spooler for my primary mail server. In the iMail Users Guide, it says:

"You must also make an entry in your hosts file (\winnt\system32\drivers\etc\hosts) which associates his IP address with his domain name.

his.i.p.address his.domainname
This way, IMail Server will attempt to deliver any mail it receives for that domain to his computer (bypassing the MX records in DNS, which point to itself and can create a mail loop)."

Is it necessary to add files to the "\winnt\system32\drivers\etc\hosts" file? It seems odd to me as most mail spoolers that I have seen do not require editing of a system file.
Has anyone experimented with this scenario to see if this is necessary?

Given that I use iMail, would not my server seem to have 0 users as no mailboxes would be set up? I expect to have several domains but no actual local users. I am simply concerned about the liscencing of the product for my uses.

Any answers or suggestions are greatly apreciated.

*Mick*