I got two domains, which are pointing on the same IP address, I can use both to connect to the server or certain port (TeamSpeak), the problem is that I would like the only one domain from those two to be working while connecting to a certain port.
Eg.
example.com points at the 11.22.33.44 — allow connection to the certain port from this domain.
sample.com points at the 11.22.33.44 — disallow connection to the port specified above from this domain.
I know this would be possible for the IP addresses, but would it be possible for the domains?
On the OS level, no, it’s not possible, because firewall is not going to do DNS lookup for every packet, as it would slow the processing down unacceptably. It may however be possible in the application you’re using, if it does DNS lookup for each connection and supports connection filtering based on DNS names. It depends on the application.
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