Frank_Rizzo - 11:52 am on Mar 25, 2011 (gmt 0)
It's the way the router tries to prevent users getting around blocked IM ports. As a secondary blocking mechanism it looks for keywords. If it sees m y m s g s in the URI it totally blocks the page.
Found a solution in another place, which suggests adding a rule to ALLOW the banned name. Haven't tried it yet but it's one for the record, i.e. some routers blocking keywords: could drive webmasters crazy if visitors say "can't access a page"