Regular expression to extract ip address from lines

Question

I would like to extract IPV4 address from each line. There could be valid or invalid ip addresses, I would like to print them all.

e.g.

Failed service from 212.345.23.234 
Successfully logged in at 13:09:89 from 12.34.76.54 
Ping from 123.567.42.56
.....
.....

Output:
212.345.23.234
12.34.76.54
123.567.42.56
.....

I need a regular expression that I can run against each line straight out like currentLine.contains(PATTERN). I don't want to tokenize the string into tokens and run RE against each token.

Please take a look at this. http://stackoverflow.com/questions/106179/regular-expression-to-match-hostname-or-ip-address — AshwinKumarS, Oct 12 '13 at 03:49
[What have you tried?](http://www.whathaveyoutried.com/) I mean *besides* asking us. — Andrew Thompson, Oct 12 '13 at 03:51

score 1 · Answer 1 · edited May 23 '17 at 11:57

1

This SO question should point you the way on how you can do match host names or IPV4 address. For IPV6, take a look at this question on SO.

edited May 23 '17 at 11:57

Community

1
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answered Oct 12 '13 at 03:51

Prahalad Deshpande

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score 0 · Answer 2 · answered Oct 12 '13 at 03:54

0

If IP is always at the and of the line you could do it this way

String ip = str.substring(str.lastIndexOf(' ') + 1);

answered Oct 12 '13 at 03:54

Evgeniy Dorofeev

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score 0 · Accepted Answer · answered Oct 12 '13 at 06:34

matching ip with regex...i had to roll my own. it seems to work for all ip ranges, though cumbersome. let me know if it fails for any case as i'll need to update my own:

\b(?:(?:2[0-5][0-5]|1[0-9][0-9]|1[0-9]|[1-9]{1,2})\.){3}(?:2[0-5][0-5]|1[0-9][0-9]|1[0-9]|[1-9]{1,2})\b

this doesnt extract anything, just matches. its up to you to do what you need.

Regular expression to extract ip address from lines

3 Answers3