I was trying to use presidio to identify and remove IP addresses, and I ran into the following issue. It was recognizing '::' as a string containing an IP address, and '2345:0425:2CA1:0000:0000:0567:5673:23b5' was not being recognized as an IP address. I ran a couple of tests as follows:

analyzer = AnalyzerEngine()

results = analyzer.analyze(text='::',
        entities=['IP_ADDRESS'],
        language='en')
print(results)

results2 = analyzer.analyze(text='2345:0425:2CA1:0000:0000:0567:5673:23b5',
        entities=['IP_ADDRESS'],
        language='en')
print(results2)


results3 = analyzer.analyze(text='2345:0425:2CA1::0567:5673:23b5',
        entities=['IP_ADDRESS'],
        language='en')
print(results3)

Output:

[type: IP_ADDRESS, start: 0, end: 2, score: 0.6]
[]
[type: IP_ADDRESS, start: 13, end: 30, score: 0.6]

This made it seem like it is just identifying an IPV6 address as any element that contains two consecutive colons. I then checked the source code, and found this in the tests:

Can the IPv6 regex be fixed?