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// Other services

Port 157: KNET/VM Command/Message Protocol

Port 157 is assigned by IANA to knet-cmp (KNET/VM Command/Message Protocol).

157

How knet-cmp works

Other services
client:157knet-cmpresponse client:157knet-cmpresponse

The client sends a request to port 157 and the knet-cmp 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
01 Security

Is port 157 dangerous?

We have no specific security note for port 157. Its risk depends on the program actually listening on it. General advice for other services services:

  • 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.
02 Registry

IANA registry entries for port 157

ServicePortTransportDescriptionReferenceUpdated
knet-cmp 157 TCP, UDP KNET/VM Command/Message Protocol - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 157, and is it reachable?

Linux

sudo ss -ltnup 'sport = :157'      # process listening on 157
sudo lsof -nP -i :157

macOS

sudo lsof -nP -i :157

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 157 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 157
netstat -ano | findstr :157

From another machine

nmap -p 157 -sV <host>
sudo nmap -sU -p 157 <host>
nc -zv <host> 157

Block it in the firewall

sudo ufw deny 157/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 157" -Direction Inbound -LocalPort 157 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 157 used for?

Port 157 is assigned by IANA to knet-cmp (KNET/VM Command/Message Protocol).

Is port 157 TCP or UDP?

Port 157 is registered for TCP and UDP.

Is it safe to open port 157?

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 157 is open?

On Linux run "ss -ltnup 'sport = :157'", on macOS "lsof -nP -i :157", and on Windows "netstat -ano | findstr :157" to see the local process. From another machine, "nmap -p 157 <host>" shows whether it is reachable.

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