Windows 10 Pls help troubleshoot port forward

[aboka]

hi, i cant make port forward working for a program. it needs port 31400-31409 for it to work. i hv done the thing below, but the program is not working. i try check if the port is open with online 'port open checking' but it say port is not open. here is what i hv done

-set fix ip for the pc to 192.168.1.188
-add port forward in router

-disable firewall
-check that im using a public ip from the isp(180.74.x.x)

im running Windows 10 Pro and using the isp default router - Fiberhome SR120-A. hv run out of ideas, pls advice. thank you,

p/s- the second port 80 is added afterward. i setup IIS and try if thats working, but same, its not open.... i hv check IIS is working as it could be connect from another pc in the LAN with its local ip:80

 

[Neemobeer]

I am not really familiar with the specific device in question, but the port forwarding rule looks fine. You can try running wireshark on the host system and check if the packets are being seen by the host to verify.

Port Forwarding Checklist

• Make sure the ISP allows port fowarding and on which ports (some ISPs will block certain or all ports on home allocated IP blocks)
• Double check your current public IP (whatsmyip.com and many other sites will tell you)
• Make sure the correct ports are open for the application
• Make sure the correct protocols are selected TCP/UDP
• Make sure the application is NAT friendly (some apps don't work well threw NAT)
• Make sure the host IP is statically set (also make sure it is outside the DHCP scope) , or a DHCP reservation
• Make sure the host firewall allows the incoming ports from the router IP
• Make sure the application is running
• Make sure the application is configured correctly

 

[aboka]

hi, sorry forget to update here - i think the issue is bcoz of private ip. as we notice we got a 100.x.x.x ip inside our router. we hv contact the isp and they say need to check and get back to us. will update here when we got news. thank you.

p/s - we hv try with another more simpler router, but with same result. its so simple that it only has IP and port number. so its real hard to mess the setting up. so we are betting on the ip address now

 

[Neemobeer]

It is certainly possible there are multiple NAT layers happening. Hard to say without knowing the full network layout.

 

[aboka]

I am not really familiar with the specific device in question, but the port forwarding rule looks fine. You can try running wireshark on the host system and check if the packets are being seen by the host to verify.

Port Forwarding Checklist

• Make sure the ISP allows port fowarding and on which ports (some ISPs will block certain or all ports on home allocated IP blocks)
• Double check your current public IP (whatsmyip.com and many other sites will tell you)
• Make sure the correct ports are open for the application
• Make sure the correct protocols are selected TCP/UDP
• Make sure the application is NAT friendly (some apps don't work well threw NAT)
• Make sure the host IP is statically set (also make sure it is outside the DHCP scope) , or a DHCP reservation
• Make sure the host firewall allows the incoming ports from the router IP
• Make sure the application is running
• Make sure the application is configured correctly

as i mention above - i suspect the issue is bcoz of the private ip address we are getting instead of public ip. anyway, would like to ask, do we need to hv 'the program' running to test if the port is open? i mean lets take port 80 for example here. its usually for webserver(IIS). so do we do we need to run IIS if we test using online tool like canyouseeme? i think so as it the tool is looking for a reply? thank you,

 

[Neemobeer]

You can use netstat locally to make sure the application is listening on the port

 

[aboka]

You can use netstat locally to make sure the application is listening on the port

hi, can you give an example to how we could do that? as i try put netstat in command prompt, i think it show us the port that is already connected. it didnt show my iis(80) in there. but its running as i could access it through the browser on another pc on the same network. thanks.

 

[Mike]

hi, can you give an example to how we could do that? as i try put netstat in command prompt, i think it show us the port that is already connected. it didnt show my iis(80) in there. but its running as i could access it through the browser on another pc on the same network. thanks.

To run the netstat command in Windows, open the Command Prompt (press the Windows key + R and type "cmd" and press Enter) and type "netstat" followed by any desired options or flags. Some common options for netstat include:

• -a: Displays all active connections and listening ports
• -b: Displays the executable involved in creating each connection or listening port
• -n: Displays active connections and listening ports using numerical IP addresses instead of resolving hostnames
• -o: Displays the process ID (PID) of the process that owns each connection or listening port

For example, to display all active connections and listening ports and the PID of the process that owns each one, you would type "netstat -a -o" in the Command Prompt and press Enter.

C:\> netstat -a -o

--

Also, I believe that one of the main issues you may be facing is that the local ports may just be random and not line up with the remote ports you are opening, but not sure.

 

[aboka]

To run the netstat command in Windows, open the Command Prompt (press the Windows key + R and type "cmd" and press Enter) and type "netstat" followed by any desired options or flags. Some common options for netstat include:

• -a: Displays all active connections and listening ports
• -b: Displays the executable involved in creating each connection or listening port
• -n: Displays active connections and listening ports using numerical IP addresses instead of resolving hostnames
• -o: Displays the process ID (PID) of the process that owns each connection or listening port

For example, to display all active connections and listening ports and the PID of the process that owns each one, you would type "netstat -a -o" in the Command Prompt and press Enter.

C:\> netstat -a -o

--

Also, I believe that one of the main issues you may be facing is that the local ports may just be random and not line up with the remote ports you are opening, but not sure.

thanks for the netstat tips. hv tried them all and hopefully be useful in future.

what do you mean by 'local ports may just be random'? it is 'fix' right? i mean for eg. IIS will always use 80 unless we change that. or if for a game, they might need port 31400 and its set/fix inside their program settings

 

[Mike]

If you need a port open for inbound traffic, that is why you would open the remote port and point it to a corresponding local port. However, some uPNP programs will open up a random local port and then use the open remote port. So the 1 to 1 local port to remote port matching may not make sense. Remember the physical firewall/router itself and the local computer are two separate devices and a one-to-one mapping of the ports may not make sense if it uses different local ports than the remote ports you are opening. This is why you need to use netstat to see what local ports are open when you are running whatever it is that uses those ports.

There are a few things you can try to troubleshoot this issue:

1. Double-check that you have set up the port forwarding correctly in your router. Make sure that the internal IP address you have specified (192.168.1.188) is the correct IP for the computer that is running the program, and that the port range (31400-31409) is also correct.
2. Try disabling any other firewalls or security software on your computer, in addition to the Windows Firewall, to ensure that they are not blocking the program's access to the specified ports.
3. Check if there is any other device on your network that is using the same IP address, you can use the command ipconfig on the command prompt to check the IP address of your computer.
4. Try to telnet to the port from another computer, if you can telnet to the port, it means that the port is open, if not, the port is closed.

telnet 192.168.1.188 31400

1. Try to check the router logs if there's any block rule or any other setting that could block your program's access to the specified ports.
2. Check if the ISP is blocking the port, some ISPs block certain ports to prevent unauthorized access to their network. If this is the case, you may need to contact your ISP to have them open the ports for you.
3. You can try to use a VPN to connect to the internet and see if that fixes the problem.
4. You can try to update the router firmware to the latest version, sometimes bugs can be fixed with firmware updates.

It's worth noting that the process of port forwarding can be complex, and it may take some trial and error to get it working properly. I hope that these suggestions will help you to resolve your issue.

 

[aboka]

@Mike hi, hv resolve the issue. my suspicion is correct - its bcoz the isp is giving us private ip. they hv help change it back to public and now all is working. but i got a friend with a similar issue, i think its bcoz of the private ip as well. do you know whether this IP is a private or public - 14.192.239.12. we try search online but not sure if it belongs to Class A private since their example is fr 10.0.0.0 -10.x.x.x.
thank you,

 

[Mike]

Only 10.0.0.0/8, 172.0.0.0/12, and 192.168.0.0/16 are private. 14.192.239.12 is a public IP.

 

[aboka]

Only 10.0.0.0/8, 172.0.0.0/12, and 192.168.0.0/16 are private. 14.192.239.12 is a public IP.

ok. probably bcoz of other issues. hv ask him to contact his ISP to help solve. thank alot =)