Port 621ESCP

ESCP service traffic uses TCP or UDP port 621.

also known as escp-ip

Technical Details

what runs on :621

ESCP is registered on port :621 over tcp and udp to Lai Zit Seng. 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 found open rarely. What's listening is often not the registered service, so check before you assume.

find what's listening on :621

this machine

# linux
sudo ss -tulpn 'sport = :621'

# macos / bsd
sudo lsof -nP -i :621

# windows (then: tasklist /FI "PID eq <pid>")
netstat -ano | findstr :621

another host

nmap -sV -p T:621 <host>
sudo nmap -sU -sV -p U:621 <host>

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

exposure of :621

risk score

1/ 10safe

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

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

tcp · udp

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

security overview

no security notes recorded for :621 yet

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

ports registered around :621, by lookups.

port	service	proto	category	risk	views
:593	HTTP RPC Endpoint Mapper	TCPUDP	Network Services	caution	26.0k
:660	Mac OS X Server Admin	TCP	Remote Access	caution	23.7k
:591	FileMaker Web Sharing	TCP	Web Services	caution	23.1k
:623	ASF-RMCP	UDP	Remote Access	caution	20.5k
:563	NNTPS	TCPUDPtls	Web Services	safe	18.1k
:636	LDAPS	TCPUDPtls	Security	caution	15.6k
:639	MSDP	TCPUDP	Network Services	caution	11.4k
:647	DHCP Failover	TCP	Network Services	caution	11.1k

risk mix of the 8 listed

2 of 8 encrypted