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Port 3820 (scp)

IANA assigns port 3820 to scp: Siemens AuD SCP.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
scp TCP Siemens AuD SCP Johann Arnold -
scp UDP Siemens AuD SCP Johann Arnold -

Registry dates for this port: registered 2004-10.

Check what is listening on port 3820

Linux: is anything listening on TCP 3820?
sudo ss -tlnp 'sport = :3820'
Linux: UDP 3820
sudo ss -ulnp 'sport = :3820'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3820
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3820 '
Windows (Command Prompt)
netstat -ano | findstr :3820
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3820 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3820
From Windows
Test-NetConnection HOST -Port 3820
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3820

Block port 3820 in the firewall

ufw
sudo ufw deny 3820/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3820 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3820 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3820' -Direction Inbound -Protocol TCP -LocalPort 3820 -Action Block
ufw
sudo ufw deny 3820/udp
iptables
sudo iptables -A INPUT -p udp --dport 3820 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3820 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3820' -Direction Inbound -Protocol UDP -LocalPort 3820 -Action Block

Related ports

3818crinis-hb3819epl-slp3821pmcp3822acp-discovery

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.