Port 4803Notateit Messaging Discovery

UDP port 4803 is assigned to Notateit Messaging Discovery.

transport
udp

single transport

in transit
cleartext

payload readable on path

assignment
official

registered with iana

risk
1/10

safe

lookups
0

rank 993 of 5,296 · top 19%

also known as notateit-disc

Technical Details

what runs on :4803

Notateit Messaging Discovery is registered on port :4803 over udp to Ean Black, assigned April 2009. We don't have a technical write-up for it beyond the IANA registry entry.

In nmap's internet-wide scan data this port is never observed open, so if it's open on your network it's more likely a custom or misconfigured service than the registered one.

find what's listening on :4803

this machine
# linux
sudo ss -ulpn 'sport = :4803'

# macos / bsd
sudo lsof -nP -i :4803

# windows (then: tasklist /FI "PID eq <pid>")
netstat -ano | findstr :4803
another host
sudo nmap -sU -sV -p U:4803 <host>

run it? the handshake, the implementations you meet in the wild and the flags that matter come from the engineers who do.

add technical details

Security Information

exposure of :4803

risk score

1/ 10safe

routine exposure. this port is rarely the way in on its own — keep it patched and logged and move on.

network services averages 2.6 across 1,592 ports — this one sits 1.6 below.

in transit

cleartext

credentials and payloads are readable by anyone on path

assignment

official

registered with iana for this service — scanners fingerprint it by number

reachable over

udp

udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite

security overview

no security notes recorded for :4803 yet

known exploits, hardening advice, what a compromise looks like — suggest an edit if you know its exposure.

the 8 most looked-up other ports in network services — 1,592 ports carry that label.

risk mix of the 8 listed

  • caution100%

0 of 8 encrypted