- 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 128: GSS X License Verification
Port 128 is assigned by IANA to gss-xlicen (GSS X License Verification).
128
How gss-xlicen works
Other servicesThe client sends a request to port 128 and the gss-xlicen 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 128 dangerous?
We have no specific security note for port 128. Its risk depends on the program actually listening on it. General advice for other services services:
IANA registry entries for port 128
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| gss-xlicen | 128 | TCP, UDP | GSS X License Verification | - | - |
// source: IANA service name and port number registry
Which program uses port 128, and is it reachable?
Linux
sudo ss -ltnup 'sport = :128' # process listening on 128
sudo lsof -nP -i :128macOS
sudo lsof -nP -i :128
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 128 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 128 netstat -ano | findstr :128
From another machine
nmap -p 128 -sV <host> sudo nmap -sU -p 128 <host> nc -zv <host> 128
Block it in the firewall
sudo ufw deny 128/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 128" -Direction Inbound -LocalPort 128 -Protocol TCP -Action Block # Windows
What is port 128 used for?
Port 128 is assigned by IANA to gss-xlicen (GSS X License Verification).
Is port 128 TCP or UDP?
Port 128 is registered for TCP and UDP.
Is it safe to open port 128?
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 128 is open?
On Linux run "ss -ltnup 'sport = :128'", on macOS "lsof -nP -i :128", and on Windows "netstat -ano | findstr :128" to see the local process. From another machine, "nmap -p 128 <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