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Port 3833 (aipn-auth)

IANA assigns port 3833 to aipn-auth: AIPN LS Authentication.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
aipn-auth TCP AIPN LS Authentication Qiang Zhang -
aipn-auth UDP AIPN LS Authentication Qiang Zhang -

Registry dates for this port: registered 2006-10.

Check what is listening on port 3833

Linux: is anything listening on TCP 3833?
sudo ss -tlnp 'sport = :3833'
Linux: UDP 3833
sudo ss -ulnp 'sport = :3833'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3833
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3833 '
Windows (Command Prompt)
netstat -ano | findstr :3833
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3833 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3833
From Windows
Test-NetConnection HOST -Port 3833
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3833

Block port 3833 in the firewall

ufw
sudo ufw deny 3833/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3833 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3833 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3833' -Direction Inbound -Protocol TCP -LocalPort 3833 -Action Block
ufw
sudo ufw deny 3833/udp
iptables
sudo iptables -A INPUT -p udp --dport 3833 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3833 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3833' -Direction Inbound -Protocol UDP -LocalPort 3833 -Action Block

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