After a long period of clinical rehab and support group meetings I think I've finally put away the trauma I've suffered at the hands of that...that thing called Exchange Server. I just need a mailserver, I don't need a domain controller -- not on my 366Mhz Celeron. Half-hour to an hour startups just don't have the same appeal to me anymore. I certainly don't need all the obscure, unfixable issues it gave me, and not all the flakiness of the POP/SMTP servers.

But I want very high reliability. There will only be a few mailboxes, but they must be up all the time, and they must always be assured that they get their mail quickly and without bizarre, flaky issues. So I'm looking at Postfix or possibly Sendmail. Do any of the more experienced users have any other recommendations?

If Postfix or Sendmail, I'd like to get my hands on a solid, complete how-to. I found a few, but these were poorly written by someone who assumed I was an expert in the config lingo -- for instance, I know what a localhost is, but why does it need to be there and what does it do? If in a single line by itself in some config file, I have no idea that is being set to localhost. If I am to administer it, I have to have a clear understanding on what these configs signify, etc.

I use sendmail, though many people speak very well of postfix. OReilly has a Sendmail book, which examines the insides of sendmail in rather gory detail. Maybe that's why so many people choose postfix instead.

For general lingo, the linux documentation project is pretty complete.

As for "localhost", it just names a particular IP address 127.0.0.1, which by general network agreement is always the local box. Since so much internal communication on a particular box is done via tcp/ip you need a tcp/ip stack present, and an IP address to communicate with, hence 127.0.0.1

In ages past, before DNS, the host file (often found in /etc) was used to connect human readable names to IP addresses, since people thought that remembering a name (where do I send that mail, anyway?) was easier than remembering the fourfold octet (oh, yes, 60.213.49.173). By agreement, localhost was always listed first in the /etc/host file with its IP address. You should find it there, even now.

Since the address 127.0.0.1 is not routable outside the physical confines of a box, it is reasonably secure, so sendmail (for example) will send and recieve mail only for localhost, until that restriction is loosened in the human accessible configuation file (senmail.mc). The sendmail docs will generally explain each line in the sendmail.mc file pretty well. You can even use Webmin (google for it) to configure sendmail in a web-based GUI.

Cheers--
Charles