Let's say I have a server with IP address that is running a network service (I don't think it is important what kind - let's say a webserver on port 80).

If I am on the server itself and connect to localhost:80, the packets will never physicaly leave the host.

What is the packet flow if I am on the server and access Will the packets leave the physical interface to the next switch/hop and come back to the server? I know that there is no need to route the packet, so a router must not be involved.

closed as off-topic by Ron Maupin May 6 at 13:00

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  • 1
    Unfortunately, what a specific host OS does is off-topic here, and each could do it differently. You could try to ask this question on Super User or one of the OS-specific SE sites. – Ron Maupin May 6 at 13:00
  • I was hoping there was some standard or recomendation from IEEE, RFC... But since I am mostly interested on how Windows does this, I will try my luck at ServerFault... Thanks – Tobias May 6 at 13:14

Depends on the server and it’s configuration, but most sane operating systems and default settings will not send the packets to the network, not even the NIC (I.e. it’s nearly the same as localhost)

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