Regular Expression to match IP address + wildcard

Question

I'm trying to use a RegularexpressionValidator to match an IP address (with possible wildcards) for an IP filtering system.

I'm using the following Regex:

"([0-9]{1,3}\\.|\\*\\.){3}([0-9]{1,3}|\\*){1}"

Which works fine when running it in LINQPad with Regex.Matches, but doesn't seem to work when I'm using the validator.

Does anyone have a suggestion as to either a better Regex or why it would work in test but not in situ?

Cheers, Ed

Answer 1

This: \\.|\\*\\. looks like the dodgy bit. Do this instead:

@"^(([0-9]{1,3}|\*)\.){3}([0-9]{1,3}|\*)$"

And to only accept 0-255 (thanks, apoorv020):

^((([0-9]{1,2})|(1[0-9]{2,2})|(2[0-4][0-9])|(25[0-5])|\*)\.){3}(([0-9]{1,2})|(1[0-9]{2,2})|(2[0-4][0-9])|(25[0-5])|\*)$

Answer 2

asp:RegularExpressionValidator does not require you to double-escape backslashes. You should try:

([0-9]{1,3}\.|\*\.){3}([0-9]{1,3}|\*){1}

Answer 3

[0-9]{1,3} would allow IP addresses of the form 999.999.999.999 . Your IP address range should allow only 0-255.
Replace all occurences of [0-9]{1,3} with ([0-9]{1,2})|(1[0-9]{2,2})|(2[0-4][0-9])|(25[0-5])
This does seem very complicated to me, and probably there are better ways of doing this, but it seems correct at first glance.

Answer 4

How about putting start and end string characters on the expression

^([0-9]{1,3}\\.|\\*\\.){3}([0-9]{1,3}|\\*){1}$