Port 11434 (Ollama)

Ollama local LLM server API.

Registered (user) port, 1024-49151 TCP Development tools Localhost or LAN only

What port 11434 is used for

Ollama local LLM server API.

Security: should port 11434 be open?

Localhost or LAN only. Ollama has no authentication. Setting OLLAMA_HOST=0.0.0.0 on a public machine lets anyone use your GPU, pull or delete models; thousands of such servers have been found exposed. Keep it on localhost or behind an authenticated proxy.

IANA assignment

Service nameProtoDescriptionAssigneeReference

ollama TCP Ollama Jesse Gross -

Registry dates for this port: registered 2025-09-26.

Check what is listening on port 11434

Linux: is anything listening on TCP 11434?

sudo ss -tlnp 'sport = :11434'

Linux / macOS: which process owns the port

sudo lsof -nP -i :11434

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':11434 '

Windows (Command Prompt)

netstat -ano | findstr :11434

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 11434 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine

nc -vz -w 5 HOST 11434

From Windows

Test-NetConnection HOST -Port 11434

Block port 11434 in the firewall

ufw

sudo ufw deny 11434/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 11434 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 11434 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 11434' -Direction Inbound -Protocol TCP -LocalPort 11434 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.