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Port 3434 (opencm)

IANA assigns port 3434 to opencm: OpenCM Server.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
opencm TCP OpenCM Server Jonathan S Shapiro -
opencm UDP OpenCM Server Jonathan S Shapiro -

Registry dates for this port: registered 2002-03.

Check what is listening on port 3434

Linux: is anything listening on TCP 3434?
sudo ss -tlnp 'sport = :3434'
Linux: UDP 3434
sudo ss -ulnp 'sport = :3434'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3434
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3434 '
Windows (Command Prompt)
netstat -ano | findstr :3434
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3434 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3434
From Windows
Test-NetConnection HOST -Port 3434
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3434

Block port 3434 in the firewall

ufw
sudo ufw deny 3434/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3434 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3434 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3434' -Direction Inbound -Protocol TCP -LocalPort 3434 -Action Block
ufw
sudo ufw deny 3434/udp
iptables
sudo iptables -A INPUT -p udp --dport 3434 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3434 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3434' -Direction Inbound -Protocol UDP -LocalPort 3434 -Action Block

Related ports

3432osdcp3433opnet-smp3435pacom3436gc-config

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