When I launch a server in my pc he is listening any ip and a port 105. If a client on another computer wants connect to the server in my computer he is using local ip address like 192.168.1.101.
If a client will use my local ip address (192.168.1.101:105) to send a request, then my server will be able to receive it?
So long as there is a network route between the two computers and no firewall getting in the way: yes.
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I created a multi-threaded client/server application that can send messages to each other at real time. Everything works perfectly, but I want to be able to send messages over the Internet. From what I understand, I need to do port forwarding to be able to make my server reachable for the clients. I then set up my port forwarding options by providing a port (9991) and then my Macbook Air's IP Address (192.168.0.1).
I then tried to connect to my server using my public server IP (let's say 197.132.20.222) and it didn't work. I then tried to see if the port forwarding worked by using this website: https://www.yougetsignal.com/tools/open-ports/ and I realized that the connection was closed. I also tried the command nc -vz 197.132.20.222 9991 while running my application and the connection is refused.
I'm using a JavaFX application, and for my server side I use a ServerSocket with port 9991. For the client side, I use a Socket and set the IP Address to my public router IP Address, and I tried to connect with another PC using mobile data to use a different network.
My firewall settings are turn off, so I really don't know what is blocking my application to connect to that port. Could it be my ISP is blocking connections? I just don't understand why my ports are blocked even with no firewalls enabled.
Can My Program Detect if the connected Client Socket on Port, say '4000', is over LAN (Local) or WAN (Remote) ?
Can InternetGetConnectedStateEx command help ?
I need it to understand if my customer is using LAN edition of my Application over WAN.
I use Delphi Seattle on Windows OS.
Regards
Allan
ALL clients connected to your server are on the same LAN as your server, otherwise they couldn't reach your server at all. But, in the case of a client connecting from the outside world through a NAT/router, the end client will be connected to the NAT/router, and then the NAT/router will be connected to your server. So, if you want to know if a client is connected to your server via the WAN, your server will need to know/discover the NAT/router's LAN IP address ahead of time, and then it can check whether a connected client's IP address matches the NAT/router's IP address or not.
When we ping to any Public IP of a router it give a reply,
we dont get reply, if we ping a local computer with its private IP of a particular network,
So is there a way so I can make direct connection or socket with a particular PC in a network.
I have heard that, I have to make connection with public IP of a particular network and the port number will decide, on which PC in that network , my request will go.
But this method is not working..
If the computer is behind a router that uses Network Address Translation (NAT) - that is, the computer has a private IP that is not visible to the internet - then you cannot ping or establish a connection to the computer from the outside. This is because the router does not know which computer you want since all the computers behind the router share the same public IP address.
The way to establish a connection in this case is to have the computer which is behind the router establish the connection to the outside computer. For example, when you go to a web site, you can do it from a computer behind a router since your computer is initiating the connection. However, the web server you are going to must have a public IP.
When a computer behind the router initiates a connection, the router does select a port number to associate with that connection so packets from the outside for that connection will go to the right computer. However, this only works for traffic on that particular connection; the port number is not a general purpose mapping to that computer.
Two computers behind the same router can establish connections with each other using the private IPs as they don't have to go through the router to do it.
You can decide with your friend who is going to be the client (the one initiation the TCP connection) and who is the server (the one receiving the TCP connection) and which port should be used (let's say X). Let's say that your friend is the server. Then he/she has to configure his/her router to redirect all the traffic to the router to port X to his/her private IP to port X (this is what Warren mentioned as NAT).
If you use a port above 1024, the server (running on your friend's PC) doesn't need root/administrator privileges.
Your program (the client) would then connect to the public IP address of your friend. He/she can check his/her public IP with: What is my IP
I am confused about TCP/IP Socket Programming. I know the internet protocols but in theory...
I am explaining my problem (what i need )
I have a server working on X.X.X.X IP Adress. And it always listens to Y PORT.
When i want to connect that server on MY PC, i have no problem because i wrote the ip adress (X.X.X.X) and the port (Y) and my PC connects..
When i connect to server server keeps my ip adress and my local ip adress.. After that connection is end.
Here is my problem starting...
As i sad my server knows my local PC informations. How can i connect to my local PC on server my web server and sent TCP or UDP packets ? I did port forwarding on my modem but i dont want it. When i did port forwarding there is no problem but i dont want it ...
Thanks for replies and sorry for my engislih if i have mistakes .
If a router/NAT sits between your server and an outside client, you MUST use port forwarding on the router. The outside client will NOT be connecting to your server's private LAN IP/Port directly, it will be connecting to the router's public WAN IP/Port instead. So the router needs to know to forward inbound packets to that IP/Port to the server's private LAN IP/Port.
A client running on your local PC is able to connect to the server because they are both on the same LAN side of the router, so the connection is direct and does not go through the router's WAN. That is not the case for clients that are on the WAN side of the router.
I am having problems connecting to my website from a source outside my local network. I had another server before running the same site. The only difference is the old one was FreeBSD and now I'm trying it on Linux.
Here is my setup: I'm using Apache2. The server is behind a Netgear router. I'm using a Freedns host name. I have ddclient updating my ip.
Here is what happens: I can look at my site from the server in Chrome or my phone connected to the local wifi. It works using either the host name or ip address. It does not load from my cell phone or from my desktop using a proxy for either the host name or the ip address (the external one from googling my ip and from the router's wan info page). When I try the proxy with the host name I get "conection timed out" error, and when I try the ip address I get "couldn't connect to host error".
Here is what I've tried: I enabled port forwarding to the server from and to port 80 to my lan ip address. I disabled the firewall on the server. I double checked that the host name is directed to the right ip address. I ensured that the ip address does indeed point to my router. I've watched wireshark on my server while trying to connect and don't see any incoming requests when I try to load it from my phone.
It seems like maybe my port forwarding isn't working, but on my router it says that that port forwarding rule is active.
I'm out of ideas as to why what else could be going wrong.