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// Other services

Port 848: GDOI

Port 848 is assigned by IANA to gdoi (GDOI).

848

How gdoi works

Other services
client:848gdoiresponse client:848gdoiresponse

The client sends a request to port 848 and the gdoi 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 848 dangerous?

We have no specific security note for port 848. 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 848

ServicePortTransportDescriptionReferenceUpdated
gdoi 848 TCP, UDP GDOI RFC 3547 -

// source: IANA service name and port number registry

03 Check it

Which program uses port 848, and is it reachable?

Linux

sudo ss -ltnup 'sport = :848'      # process listening on 848
sudo lsof -nP -i :848

macOS

sudo lsof -nP -i :848

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 848 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 848
netstat -ano | findstr :848

From another machine

nmap -p 848 -sV <host>
sudo nmap -sU -p 848 <host>
nc -zv <host> 848

Block it in the firewall

sudo ufw deny 848/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 848" -Direction Inbound -LocalPort 848 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 848 used for?

Port 848 is assigned by IANA to gdoi (GDOI).

Is port 848 TCP or UDP?

Port 848 is registered for TCP and UDP.

Is it safe to open port 848?

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 848 is open?

On Linux run "ss -ltnup 'sport = :848'", on macOS "lsof -nP -i :848", and on Windows "netstat -ano | findstr :848" to see the local process. From another machine, "nmap -p 848 <host>" shows whether it is reachable.

05 Related
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