Open Port Checker IP Or Domain Multiple ports separated by ",", with a maximum of 20 ports allowed at once. Check Description The range of port numbers is from 1 to 65535. Ports 1 to 1024 are designated by RFC 3232 as "Well Known Ports" and are commonly used for specific services. Ports from 1025 to 65535 are known as "Dynamic Ports" and can be used for establishing sessions with other hosts, as well as for custom user-defined purposes. Some common port numbers and their uses are as follows: 21: FTP file transfer service 22: SSH port 23: TELNET terminal emulation service 25: SMTP simple mail transfer service 53: DNS domain name resolution service 80: HTTP hypertext transfer service 110: Port used by POP3 (Post Office Protocol version 3) 443: HTTPS encrypted hypertext transfer service 1433: Default port for MS SQL Server database 1521: Oracle database service 1863: Port used for file transfer in MSN Messenger 3306: Default port for MYSQL 3389: Port used for Microsoft RDP (Remote Desktop Protocol) 5631: Port used for data transfer in Symantec pcAnywhere remote control 5632: Port used for scanning controlled hosts in Symantec pcAnywhere 5000: Port used by MS SQL Server If your Linux server shows applications listening on a specific port using "lsof -i:", but the online tool indicates that the port is closed, please troubleshoot the following: 1. Verify if the server's firewall allows the port. For Linux, check if iptables and firewalld are active, and temporarily disable them for testing. 2. Check if the server provider's backend has firewall settings that may be blocking the ports. 3. Confirm if the listening application uses the TCP protocol. 0 Comments 0 / 300 Submit
