FirewallD out-of-the-box Configuration choice questions (documentation?)

[Ron_E_James_D.O]

Are the choices that I see in Webmin FirewallD made by Webmin/Usermin or Ubuntu, and is there documentation somewhere that explains them? For example there are “zones” in Webmin that do not have corresponding /etc/firewalld/zones .xml files, do they do anything?

If I wanted Virtualmin to function as just a mail server (with Roundcube and possibly DNS) I would want to remove unnecessary things from the “public (default)” like anything ftp related and anything not needed for that endeavor.

Out of the box I have some that I am not sure about though:

Service dhcpv6-client (546) UDP
Service mdns (5353) UDP
Service ssh (22) TCP
Port 20 TCP
Port 2222 TCP
Port 10000-10100 TCP
Port 49152-65535 TCP

I think that I can remove all of these (except for Port 10000, which is for Usermin itself which my mail admins would need… but what are the other 99?)

Also there are several zones that seem not to have anything but “dmz” and “external” have:

Service ssh (22) TCP

“home” and “internal” have:

Service dhcpv6-client (546) UDP
Service mdns (5353) UDP
Service samba-client (138) UDP
Service ssh (22) TCP

And “work” has:

Service dhcpv6-client (546) UDP
Service ssh (22) TCP

There is only one config file in /etc/firewalld/zones, which is public.xml though, so should I take that to mean this if I do not specify some IP range as my “work” (etc) network then these ones are not being used?

SYSTEM INFORMATION
OS type and version	Ubuntu 24.0.2
Virtualmin version	7.30.4

[ID10T]

A firewall typically has a default ‘deny’ to anything not open. However, if nothing listening on a port, it is effectively closed. This is a safe guard against something like your printer and various services being open to the wider network.

@Ron_E_James_D.O

except for Port 10000

@Ron_E_James_D.O

Port 10000-10100 TCP

Note, this is a range.

Basically someone who knows more about this stuff than we do has set up some basics to get us started. I only change what I know I can do safely.

With the Virtualmin install the default firewall is firewalld. You can check out that for further documentation on the zones and such, IF that’s what you have.