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In firewall settings, local port for inbound rule is pretty obvious: that is the port you want to listen. However, remote port sounds nonsense: In typical protocol, client uses arbitrary port so restricting remote port will break your service.

https://i.stack.imgur.com/MdHzW.png image is borrowed from What are differnet between local port and remote port of firewall in Windows 2016 server? Although the image is windows firewall settings, I guess other firewalls have similar.

Is there any case to restrict client port(remote port) for inbound traffic?

user811729
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1 Answers1

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There are many software and protocols where clients may request servers from fixed ports.

  • What comes in my mind is the DNS, where client request (from port 53) a remote server (port 53). So a in-depth defense rule at your server side would be to only allow remote clients from their remote port 53.
  • I think that ldap protocol does the same: client is requesting from a fixed and well defined port.
  • You may also think of various synchronisations services (like SMB, NFS maybe, and various others..).
  • You may also define remote ports range firewalling, in example, to ensure that a client is talking from a remote unprivileged port
petitradisgris
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