[Cryptography] How to get certificates on email server?

[hbaker1]

Stupid question: I'm getting a certificate error when attempting to send email.  My email program says that the certification chain can't be verified.

Before I accept this dubious certificate, I'd like to look up this server's certificate myself & check it by hand.

How to do this?  (Either Windows or Linux is fine, since I'm not trying to actually send mail; just check the certificate.)

Thanks for any help.