Connect websocket server by LAN IP address

Question

I have set up a websockets chat with the purpose of learning. Everything is working but I can't figure this issue out.

When I supply 127.0.0.1 as the address of the connection on the client side then I can access the server from the computer that's hosting it, but when I change the address to the actual LAN address of the hosting computer I can't connect the server even from the host itself. See:

Server = new FancyWebSocket('ws://127.0.0.1:9300'); Appears to work but only the computer that's hosting the server can connect ( for obvious reasons )

Server = new FancyWebSocket('ws://192.168.1.3:9300'); No computers can connect. I confirm 192.168.1.3 is the LAN address of the hosting computer.

What address do I need to put in there so that other computers from my local network can connect?

Answer 1

I solved the problem. Since it was a combination of two answers I thought the only fair thing to do was add another answer with an explanation.

As @Mehran suggested, I have had the server address set up as 127.0.0.1 instead of the network address. After changing that to 192.186.1.3 I was able to connect from the server itself, but other machines were unable to connect. Then I did the steps from the guide provided in @vtortola's answer to add a new inbound rule into the server's firewall in order to allow that port to be used.

So finally it all works now, thank you very much for helping me. +rep to everyone!

Answer 2

I'm pretty sure this is due to the configuration of your WebSocket server. It must be listening to localhost (127.0.0.1) to accept incoming connections in which case it won't answer to those aiming 192.168.1.3.

Since you didn't mention which server you are using I can not be specific but in general there are two ways to instantiate a listening socket, binding it to a specific IP address or * to bind whatever addresses system has. You need to configure the later if you intend to answer server connections coming from any computer within your LAN.

Answer 3

It looks like a Firewall/Policies issue to me.

• IIS 7 Windows 2008, Localhost work but not local ip or external ip

Your TCP 80 could be allowed because the IIS installation will open it, that will explain why normal web browsing works. But you are trying to connect to the TCP 9300, that is very unlikely that is allowed by default.

Give a try to this: How to Open a Port in the Windows 7 Firewall , and allow that port.

Answer 4

Here are some things that you can safely assume while troubleshooting this issue:

• If the service is able to work on 127.0.0.1 on the same machine, you can assume that the problem is not in the code or the PHP configuration

• If you are not receiving an error when the server tries to bind to 192.168.1.3:9003 you can safely presume that the service is working. Try opening the Resource Monitor to see if it is actually listening on this port to confirm. To do so, go to 'Start Menu' in Windows and type 'Resource Monitor' in the 'Search programs and files' box. After opening the Resource Monitor, click the 'Overview' tab and find the name of the server process (typically 'php' if your using a CLI). With your process selected, switch over to the 'Network' tab and you will be able to see if it is listening on any ports within the 'TCP Connections' panel. This will show you what address and port it is listing on, as well as the remote address and port of any clients connected to the service.

• If you know the server is running, and you know that it is actively listening on the expected address and port, it is very likely a firewall issue within Windows or your router. Note that even though 192.168.1.3 is the IP assigned to your interface, this is not a local IP and all communication to and from 192.168.1.3 will still go through the Windows firewall, including if being sent on the same machine. If your already at this point, I would strongly suggest checking your windows firewall first. If it is not the Windows firewall, check your router to see if it is blocking the port, and also check port forwarding and other setting to make sure that the router isn't otherwise interfering. We can likely help you with router issues here, but have your router's manual handy.

HTTP is a common service port so it is very possible that the router is not blocking the port, and windows may have automatically opened it if you are using IIS. 9300 is not a common port so it is unlikely to be open by default under any situation, unless your default is "all in", which effectively means your not using a firewall.

Another thing you might try (if possible) is closing your existing HTTP service and bind to port 80 using your Websocket service, or if possible (and while exercising caution) turn off your windows firewall completely to see if it works long enough to connect.

Answer 5

In general, don't try to reach your local network IP address from your own machine. There are very confusing things that happen at the socket layer here that I'll try not to delve too far into. The OS goes out of its way to make this work. Sometimes. I would expect that you cannot reach 192.168.1.3 (the server I'm assuming) from itself. There's a translation between local endpoint addresses when you do that which complicates everything.

A network switch will typically not send a frame back down a port it just received it from, so what you're seeing when you ping your local IP in cmd prompt is a loopback shortcut the OS is taking.

Not being able to reach it from another machine causes me suspect that the socket is not bound correctly on the server. Double check that you are explicitly declaring the socket on the server (address and port), and that your're binding your listener to that socket. Also ensure that the address you're binding to is for the correct network adapter. I see this all the time with laptops or machines that have multiple connected adapters.

Unfortunately I cannot be more targeted with my response as I am unfamiliar with what a FancyWebSocket is or how it is constructed.

Answer 6

I can help you if its a linux system.

If there is no name server on the local network, it is still possible to establish a small table mapping IP addresses and machine hostnames in the /etc/hosts file, usually reserved for local network stations.

This file is available even during network outages or when DNS servers are unreachable, but will only really be useful when duplicated on all the machines on the network. The slightest alteration in correspondence will require the file to be updated everywhere. This is why /etc/hosts generally only contains the most important entries.

This file will be sufficient for a small network not connected to the Internet, but with 5 machines or more, it is recommended to install a proper DNS server.

Try adding all the 'ip:port' along with a hostname and copy the template in file /etc/hosts in all the system.

Hope it resolves the issue!