We don't want to allow special characters in the address. It really states which chars aren't allowed. The square brackets are required. The following string represents one word in the typical username. Basically, a word is either an atom or quoted string.
Some companies prefer provider-managed VPNs.
WorldCom's IP VPN Select Access Edition, however lets other IT departments leverage in-house expertise to design, manage, monitor, and upgrade their virtual networks. Cisco Secure Policy Manager lets IT managers define, distribute, enforce, and audit network-wide security policies from a central location.