PORT means “post office requisition number”. PORTS refers to the ports used on a network and the protocols used to connect devices to the network. Port Checker is an Open Source Monitoring Application that will check all your Ports and show you if they are open or closed.
What is a Port Checker?
A port checker is a tool that allows web developers to test whether or not a site is compatible with a range of devices. They do this by checking the device’s browser capabilities and making sure that the site functions properly for the device. Web designers and web developers are frequently using port checkers to ensure that the sites they build are accessible to a broad range of internet users.
What is a port number?
A port number is used to identify a specific device by the port checker. Many devices connect to the Internet through a port number. For example, your computer might connect to the Internet through a router, which in turn connects to the Internet through a modem, which in turn connects to the Internet through a broadband cable modem, and so on.
Each of these devices must know the port number that the other device expects to see and check with the port checker. The connection will fail if the modem doesn’t know what number to use.
Common network port numbers
- 5678/udp = BitTorrent
- 53/tcp = IRC, DNS
- 21/tcp = FTP
- 22/tcp = SSH
- 27/tcp = Telnet
- 110/tcp = Rlogin
- 139/tcp = Netbios
- 143/tcp = Kerberos, Microsoft RPC
- 1723/tcp = NTP
- 50000 = DHT (BitTorrent)
- 52001 = SMTP (Mail)
- 52, 100 = HTTP (Web)
- 80/tcp = Hypertext Transfer Protocol (HTTP)
- 21, 137 = DNS (TCP/UDP)
- 53, 595 = ETRN (Telephone)
- 53, 993 = IMAP (Mail)
Can ports make network connections more efficient?
Ports are just like pipes that run through a building. But instead of a pipe connecting two rooms in a home, ports connect computers to networks. A pipe has to be formed to get data to travel between those computers. But the pipe isn’t only between two rooms. It’s also between two networks (or even two computer servers).
If a person is using a Wi-Fi connection on his or her phone, there’s a pipe going between the cell phone tower (a network) and your computer (a server), but there’s also a pipe going between the cell phone tower and the router you’re using (another network). In all these cases, there’s a pipe being created between networks.
Firewalls and Ports
Like any IP address, port numbers have a numeric value that can be used to define an Internet Protocol (IP) address. The number itself is not important; what matters is the range of ports that an application can be accessed.
There is no such thing as a firewalled, untroubled port. Most security software will include a list of all the common ports that are open by default, and many applications will allow you to specify custom ports that can be accessed only by you and a trusted partner or group of partners.
What is a Port Scanner?
A port scanner or port checker is a tool used to test the availability of network services running on a computer. It scans the network ports of a target and returns a list of open ports along with the addresses associated with each port.
Most security tools today are port scanners. Port scanning is the act of sending an IP packet with a destination port number to see if the IP address is open. If the IP address is closed, the traffic is filtered. They check if there is an active listener or not. Port scans are used to find the open services and the type of software they are running. There are three types of responses:
- Open
- Closed
- Filtered
How to use the Open Port Checker tool – Port Scanner for port scanning?
The Port Scanner Tool checks the most common ports used by Windows services, Ubuntu servers, favorite games, or other software. To do so, use the following steps.
- Open the tool: Click on Port Scanner and select the Open Port Checker tool.
- Enter any domain or IP address, and the tool checks which ports are active and open and accepting requests on your IP or domain.
- Define the custom ports for checking if they are open for external requests. The default port ranges are shown in the screenshot below. You can also specify custom ports for your domain or IP.
- Click on the Scan button to start the scan.
- The results show whether the specified ports are open or closed.
TCP VS UDP Ports Scan
The TCP Port Scan (or Port Scanning) is a technique used by hackers to determine what applications or services are running on a given machine. The process involves sending a packet with a special header to the targeted host (i.e. the server) which identifies the specific port it wants to connect to.
UDP port scanning (UDP portscan) is a process of finding all open ports on a given server or computer system. While there are many ways to do this, it usually involves sending a specially crafted message to the targeted system and watching for responses.
