Port 66
sql*net and sql-net · TCP/UDP
| Range | System/well-known port (0–1023) |
|---|---|
| Protocol | TCP/UDP |
| Service | sql*net and sql-net |
Frequently asked questions
What is port 66 used for?
Port 66 is registered with the IANA for sql*net and sql-net (TCP/UDP). Description: Oracle SQL*NET IANA assigned this well-formed service name as a replacement for "sql*net".; Oracle SQL*NET.
Is port 66 a well-known port?
Yes. Port 66 is in the range 0–1023 (system or well-known ports). On Linux and macOS only privileged processes may bind to these ports.
How do I check whether port 66 is open?
Locally on Linux with ss -tulpn | grep ':66\b', on Windows with netstat -ano | findstr :66. To test a remote host use Test-NetConnection <host> -Port 66 in PowerShell or nc -zv <host> 66 on Linux/macOS.
How do I open port 66 in the firewall?
Ubuntu/Debian (ufw): sudo ufw allow 66/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=66/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 66" -Direction Inbound -Protocol TCP -LocalPort 66 -Action Allow.
IANA registry entries
| Protocol | Service | Description (IANA) |
|---|---|---|
| TCP | sql-net | Oracle SQL*NET IANA assigned this well-formed service name as a replacement for "sql*net". |
| TCP | sql*net | Oracle SQL*NET |
| UDP | sql-net | Oracle SQL*NET IANA assigned this well-formed service name as a replacement for "sql*net". |
| UDP | sql*net | Oracle SQL*NET |