IP Address with Capturing Groups

\b(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b

Assert position at a word boundary
Match the regular expression below and capture its match into backreference number 1
Match the character "." literally
Match the regular expression below and capture its match into backreference number 2
Match the character "." literally
Match the regular expression below and capture its match into backreference number 3
Match the character "." literally
Match the regular expression below and capture its match into backreference number 4
Assert position at a word boundary

Regular expression analyzed with RegexBuddy.
HTML output from RegexBuddy adapted with a PowerGREP search-and-replace sequence.