- Do not expose remote administration directly: use a VPN or a zero-trust access proxy.
- Require MFA or key-based authentication and lock out brute-force attempts.
- Log every login and alert on new source addresses.
Port 1973: Data Link Switching Remote Access Protocol
Port 1973 is assigned by IANA to dlsrap (Data Link Switching Remote Access Protocol).
1973
How dlsrap works
Remote accessThe client opens a session to port 1973: each command typed is sent to the server, which runs it and returns the output.
- Transport
- TCP · UDP
- Exposure risk
- not rated depends on the program listening
- Encryption
- Unknownnot stated by the registry
- IANA status
- Assigned1 registered service
- Range
- Registered (1024-49151)
- Category
- Remote access
Is port 1973 dangerous?
We have no specific security note for port 1973. Its risk depends on the program actually listening on it. General advice for remote access services:
IANA registry entries for port 1973
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| dlsrap | 1973 | TCP, UDP | Data Link Switching Remote Access Protocol | - | - |
// source: IANA service name and port number registry
Which program uses port 1973, and is it reachable?
Linux
sudo ss -ltnup 'sport = :1973' # process listening on 1973
sudo lsof -nP -i :1973macOS
sudo lsof -nP -i :1973
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1973 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 1973 netstat -ano | findstr :1973
From another machine
nmap -p 1973 -sV <host> sudo nmap -sU -p 1973 <host> nc -zv <host> 1973
Block it in the firewall
sudo ufw deny 1973/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 1973" -Direction Inbound -LocalPort 1973 -Protocol TCP -Action Block # Windows
What is port 1973 used for?
Port 1973 is assigned by IANA to dlsrap (Data Link Switching Remote Access Protocol).
Is port 1973 TCP or UDP?
Port 1973 is registered for TCP and UDP.
Is it safe to open port 1973?
It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Do not expose remote administration directly: use a VPN or a zero-trust access proxy.
How do I check if port 1973 is open?
On Linux run "ss -ltnup 'sport = :1973'", on macOS "lsof -nP -i :1973", and on Windows "netstat -ano | findstr :1973" to see the local process. From another machine, "nmap -p 1973 <host>" shows whether it is reachable.
Other remote access ports
:22 SSH tcp · udp · sctp · moderate risk :3389 RDP tcp · udp · critical risk :23 Telnet tcp · udp · critical risk :5900 VNC tcp · udp · critical risk :5985 WinRM (HTTP) tcp · udp · high risk :5986 WinRM (HTTPS) tcp · udp · high risk :10000 Webmin tcp · udp · high risk :89 SU/MIT Telnet Gateway tcp · udp