Port forwarding is a networking technique in which router configuration is used to allow external devices to communicate with a device on your private network. For this communication, a particular software port number is used.
Usually, when a router receives unsolicited traffic, it blocks it for security reasons. However, with port forwarding, you can instruct the router to forward a request from the public IP address at port X to device Y on the local network, at port Z.
The technique is commonly used for online gaming, accessing security cameras, remote desktops (RDP), etc. Yet, port forwarding techniques are beneficial in many ways, but they also come with numerous problems. In this article, you will learn about these common problems along with their fixes.
Common Port Forwarding Problems and Their Fixes
Many port forwarding issues can arise when it is implemented. These can put your device and network at risk of security threats. The following are some of the most common port forwarding issues.
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Port Appears Closed
Port forwarding involves opening ports (those that actively accept connections). Sometimes, the problem arises that the port on which the forwarding setup is implemented is closed. This blocks access to the services you are trying to forward to.
How to fix it?
Firstly, ensure that the port you are forwarding to is open and actively running. For this, use an online port checker. It will show you which ports on your device are open and actively accepting connections, and which are closed and not accepting connections.
If you find that the forwarding port is closed and not accepting connections immediately, visit your router settings and change the rules to set that port to open.
Ensure you click the Save/Apply button after setting up the rules. You might also have to restart the router. Once done, confirm that the settings are configured to listen on the same port you’re forwarding.
If you are new to configuration settings, do check out the steps to configure open ports on different routers. It will help you understand the complete process.
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Wrong Internal IP Address in the Rule
Sometimes a problem occurs in which the forwarding rule is pointed to the wrong IP addresses. This typically happens when the routers are configured to assign a dynamic IP address using DHCP. This gets the IP address of the device changed over time.
How to fix this?
If the cause of the issue is a dynamic IP address, it can be resolved by setting up a static IP address on your device. Alternatively, you can use the DHCP reservation feature in the router settings to prevent future IP address changes.
If you have mistakenly set up the port forwarding rules to the wrong IP address, update them with the correct internal IP address of your device. You can find the internal IP address for your device by running the following commands:
- For Windows: Run the “ipconfig” in the Windows Command Prompt.
- For Mac/Linux: Run the “ifconfig/ip a” in the Command Terminal.
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Firewall is Blocking The Port
Another problem that many face when setting up the port forwarding technique is the blocking of incoming connections by the device’s local firewall. Even when the router is forwarding connections towards the port, the firewall blocks them.
This often happens because many operating systems are by default set up to block unsolicited connections for security purposes.
How to fix?
You can fix this problem by creating new inbound rules. This can be done via the device firewall settings. However, before creating the rule, temporarily disable your firewall to test (only to ensure that the firewall is the cause of the trouble, and don’t leave it off permanently).
The procedure for creating inbound firewall rules can vary depending on the device’s operating system. Do consider watching a tutorial before taking any action.
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ISP is Blocking the Port
It is not necessary that the problem always appears on your end. Sometimes, you have set up everything perfectly, but the ports are blocked externally by your ISP (Internet Service Provider).
ISPs usually block certain hosts that are used to provide hosting services, especially on residential connections. They do this to reduce the spread of viruses, worms, and botnet traffic on their network.
How to fix this?
If a port is blocked by the ISP on which you are setting up forwarding, try using a different one. Dedicate the service to the other port you will be forwarding connections to now.
Alternatively, you can also ask your ISP for assistance with port restrictions. Ask them if they can remove the restriction or if there is another way.
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Port Forwarding Set on the Wrong Router
Sometimes people use multiple modems/routers. One that their ISP provides, and the second is a personal, separate router. In such cases, they mistakenly implement the port forwarding rule on the wrong router.
How to fix this?
This can be fixed by setting up port forwarding on the router holding the public IP. You can easily find your public IP by visiting the ‘What’s My IP’ tool. Probably, the public IP address is that of the router or modem provided by your internet service provider.
Besides the above, you can also put the second router in bridge mode. You can also set up port forwarding on both devices in the sequence: modem → router → PC.
Wrapping Up
Port forwarding is a networking technique that allows you to provide external devices with access to the services you host on your local device. Many problems can arise during implementation, such as the common ones we discussed in this article above. If you encounter one, simply implement the simple fixes we mentioned. They will help you in resolving the problem.
