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Port 16686 (Jaeger UI)

Jaeger tracing query UI.

Registered (user) port, 1024-49151 TCP Monitoring and logging Do not expose to the internet

What port 16686 is used for

Jaeger tracing query UI.

Security: should port 16686 be open?

Do not expose to the internet. No auth by default; traces can leak sensitive request data.

IANA assignment

Port 16686 is in the registered range and has no IANA assignment. The usage above is unofficial but widespread.

Check what is listening on port 16686

Linux: is anything listening on TCP 16686?
sudo ss -tlnp 'sport = :16686'
Linux / macOS: which process owns the port
sudo lsof -nP -i :16686
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':16686 '
Windows (Command Prompt)
netstat -ano | findstr :16686
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 16686 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 16686
From Windows
Test-NetConnection HOST -Port 16686

Block port 16686 in the firewall

ufw
sudo ufw deny 16686/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 16686 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 16686 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 16686' -Direction Inbound -Protocol TCP -LocalPort 16686 -Action Block

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