Open Port Check
This Open Port Check will serve as a free utility for remotely verifying a port is open or closed. It will be useful for users who wish to check to see if a server is running or a firewall or ISP is blocking certain ports.
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Open Port Check
The open port checker is a tool you can use to check domain or your external IP address and detect open ports on your connection. This tool is useful for finding out if your port forwarding is setup correctly or if your server applications are being blocked by a firewall. This tool may also be used as a port scanner to scan your network for ports that are commonly forwarded. It is important to note that some ports, such as port 25, are often blocked at the ISP level in an attempt to prevent malicious activity.
In computer networking, the protocols of the Transport Layer of the Internet Protocol Suite, most notably the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP), but also other protocols, use a numerical identifier for the data structures of the endpoints for host-to-host communications. Such an endpoint is known as a port and the identifier is the port number. The Internet Assigned Numbers Authority (IANA) is responsible for maintaining the official assignments of port numbers for specific uses.
Well-known ports: 0-1023
The following is a list of common ports. During a network security audit, port scans will be perfeormed to determine what network services are available. These services can be on different Operating systems.
| Port | TCP | UDP | Description |
|---|---|---|---|
| 20 | TCP | FTP - Data transfer - File Transfer Protocol | |
| 21 | TCP | FTP - control (command) File Transfer Protocol | |
| 22 | TCP | UDP | SSH - Secure Shell |
| 23 | TCP | Telnet protocol-unencrypted text communications | |
| 25 | TCP | SMTP - Simple Mail Transfer Protocol | |
| 42 | TCP | UDP | WINS |
| 43 | TCP | WHOIS protocol | |
| 53 | TCP | UDP | DNS - Domain Name System |
| 67 | UDP | DHCP Server - Dynamic Host Configuration Protocol | |
| 68 | UDP | DHCP Client - Dynamic Host Configuration Protocol | |
| 70 | TCP | Gopher protocol | |
| 79 | TCP | Finger protocol | |
| 80 | TCP | UDP | HTTP - Hypertext Transfer Protocol |
| 109 | TCP | UDP | POP2 - Post Office Protocol 2 |
| 110 | TCP | UDP | POP3 - Post Office Protocol 3 |
| 115 | TCP | UDP | SFTP - Simple File Transfer Protocol |
| 118 | TCP | UDP | SQL (Structured Query Language) Services |
| 119 | TCP | UDP | NNTP - Network News Transfer Protocol |
| 123 | TCP | UDP | NTP - Network Time Protocol |
| 137 | TCP | UDP | NetBIOS NetBIOS Name Service |
| 138 | TCP | UDP | NetBIOS NetBIOS Datagram Service |
| 143 | TCP | UDP | IMAP - Internet Message Access Protocol |
| 156 | TCP | UDP | SQL Service |
| 161 | TCP | UDP | SNMP - Simple Network Management Protocol |
| 194 | TCP | UDP | IRC - Internet Relay Chat |
| 220 | TCP | UDP | IMAP - Internet Message Access Protocol, version 3 |
| 389 | TCP | UDP | LDAP - Lightweight Directory Access Protocol |
| 443 | TCP | UDP | HTTPS - Hypertext Transfer Protocol over SSL/TLS |
| 444 | TCP | UDP | SNPP - Simple Network Paging Protocol |
| 445 | TCP | UDP | SMB (Server Message Block) over TCP |
| 587 | TCP | UDP | SMTP - e-mail message submission |
| 666 | TCP | UDP | Doom, first online first-person shooter |
| 873 | TCP | UDP | rsync file synchronisation protocol |
| 903 | TCP | UDP | VMware Remote Console |
| 993 | TCP | UDP | IMAPS - Internet Message Access Protocol over SSL |
| 995 | TCP | UDP | POP3S - Post Office Protocol 3 over TLS/SSL |
Registered ports: 1024-49151
Ports between 1024 and 29151 are known as the Registered Ports. Basically, programs are supposed to register their use of these ports and thereby try to be careful and avoid stomping on each other. Here are some common ports and their programs.
| Port | TCP | UDP | Description |
|---|---|---|---|
| 1243 | TCP | UDP | SubSeven (Trojan - security risk!) |
| 1352 | TCP | IBM Lotus Notes/Domino Remote Procedure Call (RPC) protocol | |
| 1433 | TCP | MSSQL (Microsoft SQL Server database management system) Server | |
| 1494 | TCP | Citrix XenApp Independent Computing Architecture (ICA) thin client protocol | |
| 1521 | TCP | Oracle database default listener, in future releases official port 2483 | |
| 1604 | TCP | UDP | Citrix ICA / Microsoft Terminal Server |
| 2049 | UDP | NFS - Network File System | |
| 2483 | TCP | UDP | Oracle database listening for unsecure client connections to the listener, replaces port 1521 |
| 3306 | TCP | MySQL database default listener | |
| 4000 | TCP | UDP | ICQ |
| 5010 | TCP | UDP | Yahoo! Messenger |
| 5190 | TCP | AOL Instant Messenger | |
| 5632 | TCP | UDP | PCAnywhere |
| 5800 | TCP | VNC remote desktop protocol-for use over HTTP | |
| 5900 | TCP | UDP | Virtual Network Computing (VNC) remote desktop protocol |
| 6000 | TCP | UDP | X11-used between an X client and server over the network |
| 6699 | TCP | Napster | |
| 6776 | TCP | UDP | SubSeven (Trojan - security risk!) |
| 7070 | TCP | UDP | RealServer / QuickTime |
| 7778 | TCP | UDP | Unreal Tournament series default server |
| 8080 | TCP | HTTP alternate/Web proxy/Caching server/Apache Tomcat | |
| 26000 | TCP | UDP | Quake |
| 27010 | TCP | UDP | Half-Life |
| 27960 | TCP | UDP | Quake III |
| 31337 | TCP | UDP | BackOrifice (Trojan - security risk!) |
Online Open Port Check Information:
- Purpose of this Tool : Network Security Audit, Open Port Check
- Intended Audience : Network Engineers, System Administrators
External Resources: