UBB.threads PHP Forum Software Community Forums UBB.threads Version 7/8 Support Referrals from firewalls?

I've noticed recently that some of my referrals look like they are from firewalls.

Delby Filseclab Firewall ( http://www.filseclab.com/ )
Sonicwall CFS Rating Engine ( reffered by http://cfsrating.sonicwall.com:8080/cfs/actions/rating.do )

This is new to me. Does anyone have any further info about this and should I be concerned about it?

Some antivirus/firewall solutions block the referrer variable from your machine to the internet; some mask it... some replace it with their own site for shameless advertising.