Now that nomachine's great nxclient is defunct on MacOS X and its new nxplayer is still in beta (and completely nonfunctional on my setup), I needed another solution to
Helsinki University's firewall prevents employees from working
Configuring the firewall by hand using iptables is quite difficult. When we still used RedHat 8.1 we have been doing it but now not anymore. We have been using yast2 now for firewall configuration. An alternative to yast2 is fwbuilder. We tried it once and it seems to work although the code it produces is quite large compared to manual configuration. An obvious advantage is that fwbuilder can be used together with many different types of firewalls and operating systems (e.g. also Mac OS X).