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// Other services

Port 6633: Cisco vPath Services Overlay

Port 6633 is assigned by IANA to cisco-vpath-tun (Cisco vPath Services Overlay).

6633

How cisco-vpath-tun works

Other services
client:6633cisco-vpath-tunresponse client:6633cisco-vpath-tunresponse

The client sends a request to port 6633 and the cisco-vpath-tun service answers.

Transport
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
Other services
01 Security

Is port 6633 dangerous?

We have no specific security note for port 6633. 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 6633

ServicePortTransportDescriptionReferenceUpdated
cisco-vpath-tun 6633 UDP Cisco vPath Services Overlay - 2012-06-11
-6633-Reserved--

// source: IANA service name and port number registry

03 Check it

Which program uses port 6633, and is it reachable?

Linux

sudo ss -ltnup 'sport = :6633'      # process listening on 6633
sudo lsof -nP -i :6633

macOS

sudo lsof -nP -i :6633

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 6633 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 6633
netstat -ano | findstr :6633

From another machine

nmap -p 6633 -sV <host>
sudo nmap -sU -p 6633 <host>
nc -zv <host> 6633

Block it in the firewall

sudo ufw deny 6633/udp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 6633" -Direction Inbound -LocalPort 6633 -Protocol UDP -Action Block  # Windows
04 FAQ
What is port 6633 used for?

Port 6633 is assigned by IANA to cisco-vpath-tun (Cisco vPath Services Overlay).

Is port 6633 TCP or UDP?

Port 6633 is registered for UDP.

Is it safe to open port 6633?

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 6633 is open?

On Linux run "ss -ltnup 'sport = :6633'", on macOS "lsof -nP -i :6633", and on Windows "netstat -ano | findstr :6633" to see the local process. From another machine, "nmap -p 6633 <host>" shows whether it is reachable.

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