Python regex to match IP range

Question

I want to match IP range using a Python regex.

For Ex. the google bot IP range as follow

66.249.64.0 - 66.249.95.255

re.compile(r"66.249.\d{1,3}\.\d{1,3}$")

I can not figure out how to do this? I found this one done using Java.

Are you trying to locate an ip address within a larger text, or do you have a string which only contains the ip address? — Joel Cornett
– Joel Cornett, Commented Jul 16, 2013 at 9:09
@Joel Cornett : I have a text file with ip addresses, I want to filter some ip addresses from it — Nilani Algiriyage
– Nilani Algiriyage, Commented Jul 16, 2013 at 9:11
Side note: if you're doing a lot of work with network addresses, you may want to check into the netaddr package. — torek
– torek, Commented Jul 16, 2013 at 9:27

Casimir et Hippolyte · Accepted Answer · 2013-07-16 09:37:29Z

1

You can use this:

re.compile(r"66\.249\.(?:6[4-9]|[78]\d|9[0-5])\.\d{1,3}$")

if you are motivated you can replace \d{1,3} by :

(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)

Explanation:

A regex engine doesn't know what a numeric range is. The only way to describe a range is to write all the possibilities with alternations:

6[4-9]  |  [78][0-9]  |  9[0-5] 

6          can be followed by    4 to 9   --> 64 to 69
7 or 8     can be followed by    0 to 9   --> 70 to 89
9          can be followed by    0 to 5   --> 90 to 95

edited Jul 16, 2013 at 9:37

answered Jul 16, 2013 at 8:59

Casimir et Hippolyte

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2 Comments

Nilani Algiriyage Over a year ago

Excellant..:) Worked Well, Thanks a lot!

Nilani Algiriyage Over a year ago

One more thing, Could you please explain this?

Joel Cornett · Accepted Answer · 2013-07-16 09:13:47Z

1

Use socket.inet_aton:

import socket
ip_min, ip_max = socket.inet_aton('66.249.64.0'), socket.inet_aton('66.249.95.255')

if ip_min <= socket.inet_aton('66.249.63.0') <= ip_max:
    #do stuff here

answered Jul 16, 2013 at 9:13

Joel Cornett

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Comments

njzk2 · Accepted Answer · 2013-07-16 09:02:55Z

0

The last digit is:

[01]?\d{1,2}|2[0-4]\d|25[0-5]

The 3rd digit is:

6[4-9])|[78]\d|9[0-5]

answered Jul 16, 2013 at 9:02

njzk2

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