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My IP Address and Port: What You Can Actually See

Wi-Fi & Home NetworkingUpdated 7 min readBy
My IP Address and Port: What You Can Actually See

Your IP address identifies the network destination; a port number identifies the application or connection at that destination. There is no single “my port” attached permanently to your public IP. Each connection uses its own source and destination ports, and your router may translate them. To check quickly, see the public IP websites see. Use a port checker only when you have a specific service and port to test.

My IP address and port do different jobs

Think of an IP address as the street address of an apartment building. A port is the apartment or office that receives a particular delivery. The comparison has one flaw: ports are numbers in software, not physical sockets. Your operating system uses them to pass traffic to the right application, and nothing physical sits behind them.

For example, a browser may connect to a web server at 203.0.113.25:443. The IP address is the destination, and 443 is the destination port for the connection. The example address is reserved for documentation, so it is not a real server you can reach.

The port belongs to the TCP or UDP transport information, not to the IP address itself. TCP (Transmission Control Protocol) supports reliable, ordered data streams. UDP (User Datagram Protocol) sends individual datagrams without promising delivery or order. TCP port 443 and UDP port 443 are separate endpoints, so a firewall rule that allows one does not allow the other. The IANA registry records service names and assignments, but a number is a convention, not a guarantee about what is running.

See the TCP and UDP specifications for port fields; IANA’s registry lists service assignments.

What does an IP address paired with a port look like?

A connection has two ends, and each end has a source and a destination. Suppose your laptop at 192.168.1.20 opens an HTTPS page. It might use local source port 53124 to contact a server on destination port 443. These are illustrative values, and your device may pick a different source port. The remote example address in the table uses TEST-NET-3, reserved for documentation by RFC 5737.

Two endpoints exchange tokens through sending trays and a service doorway. An IP address and port identify a connection endpoint.
Each connection has source and destination ports, while a server usually listens on a known destination port.
Connection detailExampleWhat it tells you
Local source192.168.1.20:53124Your device and a temporary local port
Remote destination203.0.113.25:443The server address and service port
TransportTCPWhich port namespace and transport behavior apply

The operating system tracks both ends and the transport, so many tabs can contact one website without turning into one muddled mega-tab (your browser has enough to do). Client source ports are temporary (ephemeral): the OS selects one per connection. A server usually listens on a known port.

https://example.com implies the HTTPS default, TCP 443, so the browser does not need to display it. An explicit :8443 is a non-default port. Since IPv6 addresses contain colons, URLs put an IPv6 address in brackets before the port: https://[2001:db8::1]:8443/.

RFC 9110 sets HTTP and HTTPS URL defaults to TCP 80 and 443.

Why your public IP has no fixed personal port

Your ISP (internet service provider) supplies your public-facing IP, which may change. Your router usually gives devices private addresses through DHCP (Dynamic Host Configuration Protocol), then uses NAT (Network Address Translation) so they can share the public address. RFC 1918 reserves 10.x.x.x, 172.16.x.x through 172.31.x.x, and 192.168.x.x for private IPv4 networks.

What a port check can and cannot tell you

A port is reachable only when a service is listening and firewall and routing rules allow the connection. A local listener may still be blocked by the home router, so it may not be reachable from the public internet.

What you observeLikely explanationUseful next step
Checker says closedNo service listening, firewall blocks it, or router has no forwarding ruleStart the intended service, then check local firewall and router settings
Router forwarding exists, still closedWrong device address or port, service bound to another interface, or ISP-level NATConfirm the device’s current local IP and compare router WAN IP with public IP
Checker says openA service answered on that protocol and public portConfirm it is the intended service and restrict access where possible

Use the Loqmi port checker to test a port on your own public IP while the service runs. It tests reachability at that moment. It cannot judge security or open a port. For download, upload, and latency, use the browser speed test.

Find the right address and port for your task

Start by asking which end of the connection you mean. If a website or support form asks for your public IP, use your current public IP. If it asks for a device’s local address on your Wi-Fi, find that in the device’s network settings or in the router’s connected-device list. See how to find a local IP address. A public IP lookup cannot show a device’s private address, because those addresses stay inside the local network.

If a game or support form asks for your IP and port, it normally means the address of the server or device you are trying to reach, plus its configured listening port. Get that port from the service documentation or the administrator. Do not use your browser’s temporary source port, because it can change with each connection.

Check a port without opening more than needed

For a self-check, note your public IP on Loqmi, start the service, and test its port and protocol. If the port is closed, check the listener, the firewall, and the router target. Router menus vary, so look for “Port Forwarding,” “NAT,” or “Virtual Server.”

Forward only a service you need. Keep it updated, use strong authentication, and remove the rule when you finish. If WAN and public IPs differ, ask your ISP whether CGNAT is involved.

Should I share my IP and port with support?

It can help when you troubleshoot a specific connection. Share the requested details with the service’s verified support channel, and send only what is needed. An IP and port describe a network endpoint for a connection. They do not give you a fixed personal port, and they do not prove who is using it.

IP-based location is approximate, and a port identifies an endpoint, not the person using it. Use the WebRTC leak test to see whether your browser exposes another network address through WebRTC, a real-time communication technology.

Key takeaways

  • An IP address gets traffic to a network endpoint; TCP or UDP ports help deliver it to the right service or connection.
  • Your public IP does not come with one permanent personal port. Ports belong to individual connections and may be translated by your router.
  • A port checker tests reachability at one moment. It does not start a listener, configure forwarding, or judge the service’s security.
  • Check the public IP, local device IP, service port, and transport protocol separately, so you know which part you are troubleshooting.

DNS (the Domain Name System) maps a hostname to one or more IP addresses, not usually to a custom app port. Web URLs have default ports, so a custom service needs its port listed separately. Use IP lookup for an address you already have, or read about port forwarding if you host a service behind a router.

The router tracks each connection and may translate its source port. A website can see the public IP and port used for that connection, but no universal port belongs to you. It is like asking which seat number belongs to a building: the answer depends on the visit.

With CGNAT (carrier-grade NAT), an ISP adds another shared translation layer. If the router’s WAN address differs from Loqmi’s public IP, or it shows an address in 100.64.0.0/10, CGNAT may be involved. That can block ordinary inbound forwarding; see how CGNAT works.

RFC 1918 lists private IPv4 ranges; RFC 3022 describes NAT. RFC 6598 reserves 100.64.0.0/10 for shared use.

Frequently asked questions

Does my public IP address have one permanent port number?

No. A public IP address identifies a network endpoint, while a port identifies an application or connection that uses it. Your device can use different temporary source ports for different connections, and your router may translate those ports. A port becomes meaningful when paired with a transport protocol such as TCP or UDP and the connection direction.

Why does a port checker show my IP but not my computer's private address?

An internet port check reaches the public-facing address that remote hosts can route to. A home router normally translates traffic between that address and private addresses such as 192.168.1.20. The checker tests the public side; your router's forwarding rule determines whether traffic can then reach a device inside.

Can I open a port by entering it into a port checker?

No. A checker can test whether a service is reachable on a port, but it does not create that service or change your router. The application must be listening, and the router and firewall must allow the intended traffic. Only configure services and forwarding you understand and intend to expose.

Is port 443 always the secure HTTPS port?

TCP port 443 is the standard default for HTTPS, but a port number alone does not prove what software is listening or whether a connection is safe. Services can use other ports, and UDP 443 is separate from TCP 443. Security depends on the service, encryption, configuration, and the endpoint you connect to.

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