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// Other services

Port 711: Cisco TDP

Port 711 is assigned by IANA to cisco-tdp (Cisco TDP).

711

How cisco-tdp works

Other services
client:711cisco-tdpresponse client:711cisco-tdpresponse

The client sends a request to port 711 and the cisco-tdp 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 711 dangerous?

We have no specific security note for port 711. 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 711

ServicePortTransportDescriptionReferenceUpdated
cisco-tdp 711 TCP, UDP Cisco TDP - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 711, and is it reachable?

Linux

sudo ss -ltnup 'sport = :711'      # process listening on 711
sudo lsof -nP -i :711

macOS

sudo lsof -nP -i :711

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 711 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 711
netstat -ano | findstr :711

From another machine

nmap -p 711 -sV <host>
sudo nmap -sU -p 711 <host>
nc -zv <host> 711

Block it in the firewall

sudo ufw deny 711/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 711" -Direction Inbound -LocalPort 711 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 711 used for?

Port 711 is assigned by IANA to cisco-tdp (Cisco TDP).

Is port 711 TCP or UDP?

Port 711 is registered for TCP and UDP.

Is it safe to open port 711?

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 711 is open?

On Linux run "ss -ltnup 'sport = :711'", on macOS "lsof -nP -i :711", and on Windows "netstat -ano | findstr :711" to see the local process. From another machine, "nmap -p 711 <host>" shows whether it is reachable.

05 Related
: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

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