What RegEx will match all loopback addresses?

I have an application which must warn the user upon use of localhost, 127.0.0.1, ::1, or any loopback address (the target host is used for a database-to-database connection not necessarily inside of the environment of the application). This is made complicated because addresses like the following...

127.1
127.0.01
127.0000.0000.1
127.0.0.254
127.63.31.15
127.255.255.254
0::1
0000::0001
0000:0:0000::01
0000:0000:0000:0000:0000:0000:0000:0001

...will parse properly by the consuming code, and will resolve to loopback.

What is a regular expression which will match any permutation of the IPv4 and IPv6 loopback addresses?

Solution

After a short time fiddling around in RegexBuddy (which is a truly magnificent tool for test-driven RegEx construction), I have come up with this:

^localhost$|^127(?:\.[0-9]+){0,2}\.[0-9]+$|^(?:0*\:)*?:?0*1$

This RegEx matches

The string "localhost"

localhost
LOCALHOST

These permutations of the IPv4 loopback address

127.0.0.1
127.0.0.001
127.0.00.1
127.00.0.1
127.000.000.001
127.0000.0000.1
127.0.01
127.1
127.001
127.0.0.254
127.63.31.15
127.255.255.254

These permutations of the IPv6 loopback address

0:0:0:0:0:0:0:1
0000:0000:0000:0000:0000:0000:0000:0001
::1
0::1
0:0:0::1
0000::0001
0000:0:0000::0001
0000:0:0000::1
0::0:1

This RegEx does not match

A valid server name

servername
subdomain.domain.tld

These valid IPv4 addresses

192.168.0.1
10.1.1.123

These valid IPv6 addresses

0001::1
dead:beef::1
::dead:beef:1