- Close the port if nothing on the host needs it.
- Identify the process that listens on it (commands below) before opening it in a firewall.
- Expose a service only to the networks that use it.
Port 131: cisco TNATIVE
Port 131 is assigned by IANA to cisco-tna (cisco TNATIVE).
131
How cisco-tna works
Other servicesThe client sends a request to port 131 and the cisco-tna service answers.
- Transport
- TCP · UDP
- Exposure risk
- not rated depends on the program listening
- Encryption
- Unknownnot stated by the registry
- IANA status
- Assigned1 registered service
- Range
- Well-known (0-1023)
- Category
- Other services
Is port 131 dangerous?
We have no specific security note for port 131. Its risk depends on the program actually listening on it. General advice for other services services:
IANA registry entries for port 131
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| cisco-tna | 131 | TCP, UDP | cisco TNATIVE | - | - |
// source: IANA service name and port number registry
Which program uses port 131, and is it reachable?
Linux
sudo ss -ltnup 'sport = :131' # process listening on 131
sudo lsof -nP -i :131macOS
sudo lsof -nP -i :131
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 131 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 131 netstat -ano | findstr :131
From another machine
nmap -p 131 -sV <host> sudo nmap -sU -p 131 <host> nc -zv <host> 131
Block it in the firewall
sudo ufw deny 131/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 131" -Direction Inbound -LocalPort 131 -Protocol TCP -Action Block # Windows
What is port 131 used for?
Port 131 is assigned by IANA to cisco-tna (cisco TNATIVE).
Is port 131 TCP or UDP?
Port 131 is registered for TCP and UDP.
Is it safe to open port 131?
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. Close the port if nothing on the host needs it.
How do I check if port 131 is open?
On Linux run "ss -ltnup 'sport = :131'", on macOS "lsof -nP -i :131", and on Windows "netstat -ano | findstr :131" to see the local process. From another machine, "nmap -p 131 <host>" shows whether it is reachable.
Other other services ports
:4444 Metasploit default / krb524 tcp · udp · high risk :31337 Back Orifice / elite tcp · udp · high risk :1 TCP Port Service Multiplexer tcp · udp :5 Remote Job Entry tcp · udp :9 Discard tcp · udp · sctp · dccp :11 Active Users tcp · udp :17 Quote of the Day tcp · udp :18 Message Send Protocol (historic) tcp · udp