firewall: reword DNS resolution note

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Corey Ford 2025-03-18 19:12:09 +01:00 committed by GitHub
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@ -40,8 +40,8 @@ If the qube is running, you can open Settings from the Qube Popup Menu.
ICMP and DNS are not accessible in the GUI, but can be changed via `qvm-firewall` described below.
Connections to Updates Proxy are not made over a network so can not be allowed or blocked with firewall rules, but are controlled using the relevant policy file (see [R4.x Updates proxy](/doc/software-update-vm/) for more detail).
Note that if you specify a rule by DNS name it will be resolved to IP(s) *at the moment of applying the rules*, and not on the fly for each new connection.
This means it will not work for servers using load balancing, and traffic to complex web sites which draw from many servers will be difficult to control.
Note that if you specify a rule by DNS name it will be resolved to IP(s) *at the moment the rules take effect* (including each time the qube or netvm starts), and not on the fly for each new connection.
This means it will not work reliably for servers that have different IPs at different times as a result of DNS-based load balancing.
Instead of using the firewall GUI, you can use the `qvm-firewall` command in Dom0 to edit the firewall rules by hand.
This gives you greater control than by using the GUI.