Certificates for newbies?

[Stergil]

I have a very basic understanding of how and why certificates are used. I have Zimbra installed at home for me, myself, and I. I've recently changed to using https access since lately I've been accessing my mail server externally more and more.

When attempting to access my mail server from a friend's or client's machine I get a certificate error citing that the user is unknown or that it's not a trusted signer.

Is this to be expected unless I somehow purchase a commercial certificate from somewhere? Or is this a case of me simply not knowing what I'm doing? I wouldn't be terribly surprised if it was the latter of the two

Any direction is appreciated. I've done some searching and most of what I found was dealing with expired or commercial certs.

[mmorse]

It's not you different browsers give different warning levels for self-signed certs (one's not signed by a recognized certificate authority). You can install it as a trusted certificate on your machine, but yes when working from a friends you'll still get the prompt. Let's say you're using Windows, IE7 for instance got a lot more harsh in their warnings...especially if it's not commercial & the server/common name doesn't match the url entered in your browser. Firefox & Safari are a tad nicer in their warnings

IE7:
HTTPS Security Improvements in Internet Explorer 7
IEBlog : Better Website Identification and Extended Validation Certificates in IE7 and Other Browsers
More on the Extended Validation Certificates aka: 'green-bar' initiative: Extended Validation Certificate - Wikipedia, the free encyclopedia

[Stergil]

I have a matching common name to domain, but it's self signed and I'm a nobody, so I always get the warning/error I guess.

I always use Firefox, and when seeing it in IE at a client's site it seemed a bit more harsh, like you suggested.

Thanks much for your input, and for the urls!