The fire-walling in Linux may be deadly. An improper configuration may bring the station to its knee. One command that may save your day is
netconf --resetfw
This command deactivates all fire-walling rules. It does not affect the configuration, but only the working set.
netconf --update
will reactivate the rules. You may need to use those two commands to check out if a network malfunction is caused by your fire-walling rules or not.