A quick google of the resolved hostname for that IP (crl.verisign.net) explains what is going on. It's not specific to mIRC-- in fact, it's probably coming directly from Windows, prior to mIRC making SSL connections using the SSL libraries:

http://www.dslreports.com/faq/7998

Note that the other google results are just as interesting, and hint that this is also baked into .NET (probably through the same libraries mIRC uses).