does http://localhost/myapp from a desktop PC on a Windows network go through network firewall?

Question

I am trying to find out if the (hardware) firewall on our network would be scanning packets when I type this in a browser window:

  http://localhost:51502/myapp.

Would "localhost" packets be strictly local so the firewall would not be implicated, and neither would the network DNS server?

"myapp" is referring only to resources that can be found on the local PC; it is not linking to external sites or pulling data or images or anything else from servers on the network.

Answer 1

In a normal configuration, localhost is resolved by Windows internally, to 127.0.0.1 and ::1. This name doesn't even exist on DNS servers.

Both these addresses are "loopback" addresses, meaning that packets sent to them are returned by the OS (over the "Loopback Pseudo-Interface" on Windows) and never leave your computer or reach any hardware firewalls.

They can still be captured by paranoid software firewalls which hook directly into the OS network stack.