How to Check Router Ports: A Step-by-Step Guide
Every single device on your network communicates via ports. If there is an issue, your game doesn’t connect, your camera is offline, or the remote desktop has stopped working, chances are, the problem involves a port. Learning how to check network router ports is the only reliable way to determine if an open port is causing the issue or not. This guide will walk you through the entire process and tell you everything you need to know about the ports on your router.
The Guide to Checking the Ports on Your Router
What Are Router Ports?
A port is a logical construct that has numbers assigned to it. There are two types of ports – physical and logical. Physical ports are found on the body of your router. Usually, there is a WAN port (where you connect the internet cable) and several LAN ports (to connect your PCs).
Logical ports usually have numbers assigned to them (from 0 to 65535).
They have specific purposes (such as 80 – web traffic, 443 – encrypted web traffic, and 25 – email traffic). Sometimes people refer to these logical ports as TCP or UDP ports (they use the Transmission Control Protocol or the User Datagram Protocol). When someone asks to check the ports on the router, they mean the logical ports.
However, sometimes even the physical ports can be an issue. If your PC is connected via a cable, ensure it is tightly plugged into the port. Routers usually have 4 LAN ports and 1 WAN port.
Why Checking Router Ports Is Important
There are two main reasons that make checking the router ports a necessary endeavor. First, it may reveal which port is blocking a specific service. If the required port is closed, that service will not work. In most cases, no error message will appear, making it difficult to identify the problem. Secondly, it may show if there are any open ports that should not be.
How to Check the Ports on the Router
Checking the router ports is a reasonably simple process. The procedure may vary for different models.
Find the IP Address of Your Router
First, you need to obtain the IP address of your router. Windows users can do that by opening the Command Prompt and typing ip config. The default gateway will have an IPv4 address in the format of 192.168.x.x. This is your router’s IP. The process is slightly different for MAC OS X. You need to go to System Preferences > Network > Details and look for the TCP/IP address.
Log in to the Router
You can now proceed to your router’s interface by typing in the obtained IP address in the address bar of Chrome or any other browser. You will be asked to enter the username and password for the router’s interface. The default username and password are usually found on the back of the router. If you have changed them and do not remember the new credentials, you will have to perform a hard reset on the router and reconfigure it.
Open the Port Forwarding Section
Once you are in the router’s interface, you need to find the Port Forwarding / Virtual Server section. It is also called NAT Forwarding, Applications and Gaming, or Firewall > Port Rules. The name of the section may vary depending on the brand.
The section lists all the ports that are forwarded to specific IPs behind the router. You can see what applications are being used. If the table is empty, it means that no ports are forwarded.
Read What’s Open
Take note of the port number, protocol (TCP, UDP, or both), and the private (internal) IP address. Make sure those IPs are still correct as they were when the port was opened. If the PC that was supposed to receive the data via this port has changed its IP address, the new owner of this IP will be able to use this port for their own means.
Run an External Port Scan
Now, you need to find the public IP of your network. If it is different from the private IP behind the router, a port scan will show if any external application may be using those ports. You can do a port check via an online scanner. Enter your public IP address there and make sure that all required ports are closed (if they should be) or open (if they should be).
Check What's Using a Port Locally
On Windows, open Command Prompt as administrator and run:
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Ip config - find the gateway
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netstat -ano - list active connections, ports, and process IDs
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netstat -ano | findstr :80 — check activity on port 80
Take the process ID from the last column and match it in Task Manager. That tells you which program owns the port.
On Mac or Linux, run lsof -i 80. Same idea, different command.
Quick Command Reference
Handy if you test ports often.
Windows (Command Prompt, as administrator):
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Ip config — find the gateway
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netstat -ano — every active port plus the owning process ID
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netstat -ano | findstr:43 — one port only
Mac and Linux (Terminal):
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netstat -an | grep LISTEN — ports in a listening state
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lsof -i:443 — the program using a specific port
External: an online port checker, using your public IP.
Write the results down somewhere. A short log turns the next port check into a two-minute job instead of a twenty-minute one.
How to Close a Port You Don't Need
Closing a port is a quick procedure and a good idea to secure your network.
Refer back to the Port Forwarding Page.
Delete the entry for the port you no longer need. (Note: It's a good idea to actually delete the entry, rather than turn it off - disabled entries can sometimes be re-enabled by mistake.)
Once the port has been deleted, re-test your external scan to ensure the port is closed.
If the entry corresponds to a service you need, leave it alone. However, make sure the internal IP address in the entry corresponds to the correct machine, as it can be a security risk to have a port forwarded to the wrong machine.
Which Ports Should I Open?
Most home routers include a built-in firewall that blocks unsolicited inbound traffic while allowing return traffic for connections you started from inside your network. Because of this, you usually do not need to forward ports for normal outgoing connections. Port forwarding is mainly needed when a service on your network must accept connections from outside, such as a game server or certain CCTV systems. As such, you don't need to forward any ports to allow traffic out - only ports that need to be accessed from outside (inbound) need to be forwarded, such as a game server or CCTV camera.
There are some ports that never need to be opened, such as remote desktop (3389) and file sharing (445), as they're common attack vectors. If you need remote access to your computer, consider using a VPN instead.
Remember, port forwarding means any traffic sent to that port is sent to your machine, whereas port triggering will only open the port when the program requests it. If your firewall supports it, and the program you're using supports it, it's a good idea to use port triggering instead.
Common Mistakes
Forwarding a range of ports when a single port is needed. This can lead to unnecessary exposure and risk.
Leaving old entries in place:
Entries from years ago that you forgot about can leave security holes in your network. If you forwarded a port for a game server that you no longer use, make sure to delete the entry.
Leaving UPnP enabled:
While it's a convenient way to forward ports, there are some serious security risks involved. Only enable UPnP if you know what you're doing.
Not double-checking the external scan:
The external scan may show different results from what you see on the router GUI, as the router's status page may not always be accurate. It's a good idea to run the external scan periodically to ensure no unwanted ports are opened.
Thinking there's something wrong when there isn't:
While some entries may show up on a port scanner, they're not always accurate. If you're not sure whether a port is open or not, try restarting your router and re-scanning.
Wrapping Up
Checking router ports helps you find connection problems and spot unnecessary exposure on your network. Start by reviewing the port forwarding rules on your router, then use local commands and an external port scan to confirm what is actually open. Remove old forwarding rules and avoid opening ports you do not need.
For business networks, regular port and firewall checks can help prevent misconfigured rules from creating unnecessary security risks. If you need help reviewing your router, firewall, or port forwarding setup, MikroTik router suppliers like Ultra Tech can help assess your network and configure suitable MikroTik solutions for secure and reliable connections.
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Our professional team can review your current port forwarding entries, assess your network, make recommendations, and assist with any connection issues you may have. No matter how big or small your network is, or what kind of support you need, we can help you get the most security and flexibility out of your network firewall.