Should I use a firewall on Linux laptop? (specifically for travelling)

[exaCORE]

Yes. It is good to disable unnecessary ports to reduce attack surface. See SkewedZepplins post here:

@SkewedZeppelin

• ensure your firewall is set proper:
• for Windows Public should be ok, someone else can confirm
• last I used Mac OS X, it had a stealth option
• for firewalld or ufw set inbound to drop
• ensure no unnecessary ports are opened
• ensure any running services have proper authentication/access controls
• remember anyone on the network can (try to) toy with your traffic
• remember anyone listening on the radio can observe all past/present/future traffic
• WPA2/3-EAP and WPA3-PSK largely mitigate this