CODEWITHSUNDEEP
c#regexip
Russ Clark
Russ Clark

Reputation: 13460

Regular Expression to Match IP Subnet

I need a C# regular expression that will match an IP Subnet, like "127.65.231", but not match an IP Address on the subnet, like "127.65.231.111". I had found this Regex for an IP Address:

@"\b\d{1,3}.\d{1,3}.\d{1,3}.\d{1,3}\b"

and was thinking I could just delete the part that checks the last octet, like this:

@"\b\d{1,3}.\d{1,3}.\d{1,3}\b"

but this matches both the IP Address and the Subnet. Can anyone help with this?

Upvotes: 4

Views: 2740

Answers (2)

Jonesopolis
Jonesopolis

Reputation: 25370

@"^\d{1,3}\.\d{1,3}\.\d{1,3}$"

use Line Anchors. Add ^ at the beginning of your Regex, and $ at the end, to verify the beginning and end of the input.

This will match 127.65.231 but not 127.65.231.111

Upvotes: 0

p.s.w.g
p.s.w.g

Reputation: 149050

You might try using a lookahead. Also, please escape the . characters—otherwise it would match any character:

@"\b\d{1,3}\.\d{1,3}\.\d{1,3}(?=\.\d{1,3})\b"

This will match any string like 127.65.231 as long as it's followed by a string like .111.

Upvotes: 1

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