Port 1021
exp1 · DCCP/SCTP/TCP/UDP
| Range | System/well-known port (0–1023) |
|---|---|
| Protocol | DCCP/SCTP/TCP/UDP |
| Service | exp1 |
| Reference | 1, RFC 4727, RFC 6335 |
Frequently asked questions
What is port 1021 used for?
Port 1021 is registered with the IANA for exp1 (DCCP/SCTP/TCP/UDP). Description: RFC3692-style Experiment 1.
Is port 1021 a well-known port?
Yes. Port 1021 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 1021 is open?
Locally on Linux with ss -tulpn | grep ':1021\b', on Windows with netstat -ano | findstr :1021. To test a remote host use Test-NetConnection <host> -Port 1021 in PowerShell or nc -zv <host> 1021 on Linux/macOS.
How do I open port 1021 in the firewall?
Ubuntu/Debian (ufw): sudo ufw allow 1021/tcp. Fedora/RHEL (firewalld): sudo firewall-cmd --add-port=1021/tcp --permanent, then firewall-cmd --reload. Windows (PowerShell as administrator): New-NetFirewallRule -DisplayName "Port 1021" -Direction Inbound -Protocol TCP -LocalPort 1021 -Action Allow.
IANA registry entries
| Protocol | Service | Description (IANA) |
|---|---|---|
| TCP | exp1 | RFC3692-style Experiment 1 |
| UDP | exp1 | RFC3692-style Experiment 1 |
| SCTP | exp1 | RFC3692-style Experiment 1 |
| DCCP | exp1 | RFC3692-style Experiment 1 |