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@dfee
Last active Nov 24, 2022
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Python IPV4 / IPV6 Regular Expressions (REGEX)
# Constructed with help from
# http://stackoverflow.com/questions/53497/regular-expression-that-matches-valid-ipv6-addresses
# Try it on regex101: https://regex101.com/r/yVdrJQ/1
import re
IPV4SEG = r'(?:25[0-5]|(?:2[0-4]|1{0,1}[0-9]){0,1}[0-9])'
IPV4ADDR = r'(?:(?:' + IPV4SEG + r'\.){3,3}' + IPV4SEG + r')'
IPV6SEG = r'(?:(?:[0-9a-fA-F]){1,4})'
IPV6GROUPS = (
r'(?:' + IPV6SEG + r':){7,7}' + IPV6SEG, # 1:2:3:4:5:6:7:8
r'(?:' + IPV6SEG + r':){1,7}:', # 1:: 1:2:3:4:5:6:7::
r'(?:' + IPV6SEG + r':){1,6}:' + IPV6SEG, # 1::8 1:2:3:4:5:6::8 1:2:3:4:5:6::8
r'(?:' + IPV6SEG + r':){1,5}(?::' + IPV6SEG + r'){1,2}', # 1::7:8 1:2:3:4:5::7:8 1:2:3:4:5::8
r'(?:' + IPV6SEG + r':){1,4}(?::' + IPV6SEG + r'){1,3}', # 1::6:7:8 1:2:3:4::6:7:8 1:2:3:4::8
r'(?:' + IPV6SEG + r':){1,3}(?::' + IPV6SEG + r'){1,4}', # 1::5:6:7:8 1:2:3::5:6:7:8 1:2:3::8
r'(?:' + IPV6SEG + r':){1,2}(?::' + IPV6SEG + r'){1,5}', # 1::4:5:6:7:8 1:2::4:5:6:7:8 1:2::8
IPV6SEG + r':(?:(?::' + IPV6SEG + r'){1,6})', # 1::3:4:5:6:7:8 1::3:4:5:6:7:8 1::8
r':(?:(?::' + IPV6SEG + r'){1,7}|:)', # ::2:3:4:5:6:7:8 ::2:3:4:5:6:7:8 ::8 ::
r'fe80:(?::' + IPV6SEG + r'){0,4}%[0-9a-zA-Z]{1,}', # fe80::7:8%eth0 fe80::7:8%1 (link-local IPv6 addresses with zone index)
r'::(?:ffff(?::0{1,4}){0,1}:){0,1}[^\s:]' + IPV4ADDR, # ::255.255.255.255 ::ffff:255.255.255.255 ::ffff:0:255.255.255.255 (IPv4-mapped IPv6 addresses and IPv4-translated addresses)
r'(?:' + IPV6SEG + r':){1,4}:[^\s:]' + IPV4ADDR, # 2001:db8:3:4::192.0.2.33 64:ff9b::192.0.2.33 (IPv4-Embedded IPv6 Address)
)
IPV6ADDR = '|'.join(['(?:{})'.format(g) for g in IPV6GROUPS[::-1]]) # Reverse rows for greedy match
tests = [
'1::',
'1:2:3:4:5:6:7::',
'1::8',
'1:2:3:4:5:6::8',
'1:2:3:4:5:6::8',
'1::7:8',
'1:2:3:4:5::7:8',
'1:2:3:4:5::8',
'1::6:7:8',
'1:2:3:4::6:7:8',
'1:2:3:4::8',
'1::5:6:7:8',
'1:2:3::5:6:7:8',
'1:2:3::8',
'1::4:5:6:7:8',
'1:2::4:5:6:7:8',
'1:2::8',
'1::3:4:5:6:7:8',
'1::3:4:5:6:7:8',
'1::8',
'::2:3:4:5:6:7:8',
'::2:3:4:5:6:7:8',
'::8',
'::',
'fe80::7:8%eth0',
'fe80::7:8%1',
'::255.255.255.255',
'::ffff:255.255.255.255',
'::ffff:0:255.255.255.255',
'2001:db8:3:4::192.0.2.33',
'64:ff9b::192.0.2.33',
]
# IPV6ADDR Tests
def test_individual(tests):
for t in tests:
assert re.search(IPV6ADDR, t).group() == t
# MULTILINE
def test_multiline(tests):
_tests = tests[:]
for t in re.findall(IPV6ADDR, ' '.join(tests)):
_tests.remove(t)
assert not _tests
test_individual(tests)
test_multiline(tests)
@fooofei
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fooofei commented Sep 29, 2019

This regex cannot match a valid IPv6 address 0:0:0:0:0:0:10.0.0.1

@cabg2101
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cabg2101 commented Jul 30, 2020

Line 22: replace r'(?:' + IPV6SEG + r':){1,4}:[^\s:]' + IPV4ADDR with r'(?:' + IPV6SEG + r':){1,6}:?[^\s:]' + IPV4ADDR, and that will cover fooofei's corner case.

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