Can a port assigned through port forwarding still be used by other computers?

Question

So say if I were to add a entry to the port forwarding table linking port 88 to ip address 192.168.4.6, could other computes still access that port or would that port become exclusive to that ip address?

Answer 1

Port forwarding is to one computer only, incoming port only...

That is, port 88 outgoing is still ok for any PC on the network, but incoming ports from the internet can only be forwarded to one PC. Think of it, how would a router know which PC was to get port 88 when an incoming packet came along, flip a coin? Forwarding basically says "when an incoming packet for port 88 comes in, send it to PC xxx, they want it..."

Answer 2

I don't know the answer but I'd like to have the previous answer clarified if the person who responded doesn't mind.



The way I understand the NAT function of a router, it keeps a record of all outgoing requests etc. When the requested data is returned it forwards it to the appropriate PC on the LAN. For that reason all PCs on the local network should be able use the same ports.... they all should be able to browser the internet, access email etc. etc. When unsolicited data arrives at the router, it blocks it regardless of the port as it wasn't requested by a PC on the LAN.

In order to allow unsolicited data through on a specific port, the port must be forwarded to a particular PC on the LAN.... hence the need for port forwarding. However to my way of thinking it doesn't necessarily follow that requested data using a port which has been forwarded to a different PC must be sent to that PC even if it was requested by another computer. It seems reasonable that if computer "A" sent out a request on port "X", that a router would forward the requested data to computer "A" even if port "X" had been forwarded to computer "B". It might just be the unsolicited data coming in on port "X" that would be automatically forwarded to computer "B", rather than the data being blocked as it normally would.



I've no idea if port forwarding over-rides the router's normal NAT function in respect to the forwarded port. It'd be interesting to know for sure. Maybe it depends on how an individual router works rather than it being a hard and fast rule either way? I might have to try to test it out some day.

Answer 3

Port forwarding is run by ability of the Router as a replace of a working laptop or laptop, so it is not going to pass with you back homestead, yet you are able to disable it by ability of a click of a button once you may. to describe it a splash, port forwarding makes it so any site visitors coming in from "outdoors" your community (internet / ISP), with a holiday spot port which you unique, to pass to the specified "inner" IP handle (on your place), being your gadget. So incredibly if enable's say you're installation a Minecraft server, in case you enable port forwarding for the Minecraft Server's port (which purely that application makes use of) which ability if somebody tries to connect with :25565 then it is going to consistently be directed on your laptop. If it is only Minecraft then it is incredibly ok, I propose in case you overwrote yet another port forward rule that he already had in place for his very own server then that could desire to screw issues up (wherein case you may only replace your port to some thing else then forward that), whether if it is a few thing incredibly uncomplicated like say port 80 (that's HTTP), then that routes fairly a lot each internet-based site visitors to one gadget which might actual screw issues up. So incredibly, once you're port forwarding non nicely-consumer-friendly ports (that are >1024) it is advantageous yet once you're forwarding nicely-consumer-friendly ports (<1024) then you definately could be careful. :)