(                 # $1 - first IP
\d{1,3}     # 1-3 digits
(?:              # grouping for rep count
\.                # dot
\d{1,3}     # 1-3 digits
){3}          # three more times
(?:             # optional extra grouping
\/               # a slash
\d+           # 1st port number
)?              # close extra grouping
)                # close group around 1st IP
[                # set up character class
\s              # whitespace
a-zA-Z    # letters
\W           # non-word characters
]+             # end character class
(                # $2 - 2nd IP
\d{1,3}   # 1-3 digits
(?:            # grouping for rep count
\.              # dot
\d{1,3}   # 1-3 digits
){3}         # three more times
(?:            # optional extra grouping
\/              # a slash
\d+           # 2nd port number
)?              # close extra grouping
)                # close group around 2nd IP
/x )           # specify /x