In extending the web front end to support IPv6, I came across the
issue of how to specify the netmask.

Currently, a bit mask, in dotted quad form e.g.,, is
expected to specify the netmask. IPv6 does not use a bit mask but
instead uses a prefix size, e.g., ::1/128 which is the address for
localhost. (Not only is a similar bit mask format not defined for
IPv6, it is not practical either as the netmask for localhost if
defined would be
On the other hand, IPv4 can use either a bit mask or a prefix
specification, with the later actually being preferred since the
switch to CIDR.

I propose we change the front-end (and back-end if needed) to switch
to the prefix notation for specifying the bit mask as it is the
current best practice for IPv4 and the only notation for IPv6. Any


Mark Gardner

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