Interface problems with NTP, numeric IPv6 address, and allowed characters.

[bfeitell]

There is an inconsistency between the way the GUI parses IPv6 inputs dues to a character filter on the General Setup page.

A numeric IPv6 address may be added under Services/NTP, and the system will use the IPv6 address just fine.  Due to the character limits in place on the System/General Setup page, the valid IPv6 address entered on the Services/NTP page breaks future changes to the System/General Setup page, which will thrown an error on save.

The General Setup page filter excludes the colon ":" which is necessary to input a properly formatted numeric IPv6 address.

Attempts to save on the General Setup page show an error as follows:

(edited for clarity, spelling, and grammar)