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Port 1894 (o2server-port)

IANA assigns port 1894 to o2server-port: O2Server Port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
o2server-port TCP O2Server Port Tim Howard -
o2server-port UDP O2Server Port Tim Howard -

Check what is listening on port 1894

Linux: is anything listening on TCP 1894?
sudo ss -tlnp 'sport = :1894'
Linux: UDP 1894
sudo ss -ulnp 'sport = :1894'
Linux / macOS: which process owns the port
sudo lsof -nP -i :1894
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':1894 '
Windows (Command Prompt)
netstat -ano | findstr :1894
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1894 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 1894
From Windows
Test-NetConnection HOST -Port 1894
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 1894

Block port 1894 in the firewall

ufw
sudo ufw deny 1894/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 1894 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 1894 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 1894' -Direction Inbound -Protocol TCP -LocalPort 1894 -Action Block
ufw
sudo ufw deny 1894/udp
iptables
sudo iptables -A INPUT -p udp --dport 1894 -j DROP
nftables
sudo nft add rule inet filter input udp dport 1894 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 1894' -Direction Inbound -Protocol UDP -LocalPort 1894 -Action Block

Related ports

1892childkey-ctrl1893elad1896b-novative-ls1897metaagent

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