Port 11434 OLLAMA
Port 11434 is the IANA-assigned ollama port for Ollama (TCP).
What is port 11434 used for?
Port 11434 is assigned to ollama and uses TCP. The IANA registry describes the service as “Ollama”. It sits above the registered range, where most numbers are transient client ports. A fixed high port is worth documenting precisely because tooling often assumes the default.
Ports are the transport-layer address a service listens on. A client that wants to reach ollama connects to port 11434. If nothing is listening, the connection is refused. That is why a port conflict appears whenever two processes try to bind the same number.
Use the commands below to confirm whether port 11434 is actually in use before you change firewall rules. Blocking the port stops new inbound traffic at the firewall, but it does not stop a local process from listening, and it does not remove the service from the machine.
Source: IANA Service Name and Transport Protocol Port Number Registry. Registered assignee: [Jesse_Gross].
Check and block port 11434
Copy-ready commands for the protocols assigned to this port. Run the check first, then block only what should not be reachable.
Check on Linux
sudo ss -tlpn 'sport = :11434'Check on Windows
Get-NetTCPConnection -LocalPort 11434 -State Listen -ErrorAction SilentlyContinueBlock with UFW
sudo ufw deny 11434/tcpBlock with iptables
sudo iptables -A INPUT -p tcp --dport 11434 -j DROPThese commands are examples for a typical host. Check the listener before you change firewall rules, and persist iptables rules with iptables-save or netfilter-persistent. On Windows, use Windows Defender Firewall or New-NetFirewallRule for persistent blocks. The iptables rules here cover IPv4; mirror them with ip6tables if IPv6 is enabled.
Is port 11434 safe to expose?
Ollama's local API has no authentication by default and can expose models and prompt execution. Do not publish it without a protected reverse proxy. Treat this port as sensitive. Restrict it to trusted networks or a VPN, require authentication and logging, and never expose it directly to the public internet without a hardened gateway in front.
Where port 11434 is usually used
Most traffic on port 11434 falls into these scenarios. The demo below is a safe way to confirm the listener before you change anything.
- Local inference servers exposing models to a desktop app or script.
- Internal chat interfaces and automation calling a self-hosted model.
- Evaluating models on a workstation or a private GPU host.
List local models
The Ollama API returns JSON without authentication on the loopback interface; keep it there unless a proxy adds access control.
curl -s http://127.0.0.1:11434/api/tagsCommon problems with port 11434
Connection refused or timed out
Refused usually means the host is reachable but nothing is listening on port 11434. A timeout more often means a firewall drop, a wrong host or a service bound to a different interface.
Port already in use
Find the process holding the port with sudo ss -tlpn 'sport = :11434' or sudo lsof -i :11434. Stop that process or configure it to bind another port; killing it without identifying it can take down a production service.
Firewall rule did not survive a reboot
UFW and Windows Firewall keep rules across restarts. Raw iptables rules do not: save them with iptables-save or the netfilter-persistent package, and re-apply after upgrades that reset the ruleset.
The port is blocked but still reachable
A firewall rule filters inbound traffic; it does not close the listener. Confirm with the check command above and bind the service to 127.0.0.1 when only local clients need it.
Port 11434 at a glance
| Port number | 11434 |
|---|---|
| Service name | ollama |
| Transport protocol | TCP |
| Category | AI and local models |
| Range | High port (10001–65535) |
| Risk level | High |
| Registered assignee | [Jesse_Gross] |
| Registry description | Ollama |
| Source | IANA Service Name and Transport Protocol Port Number Registry |
Frequently asked questions
What is port 11434 used for?
Port 11434 (OLLAMA) uses TCP. Ollama.
How do I check if port 11434 is open?
On Linux run `sudo ss -tlpn 'sport = :11434'`. On Windows run `Get-NetTCPConnection -LocalPort 11434 -State Listen -ErrorAction SilentlyContinue` in PowerShell. If the port is open, the output shows a process listening on port 11434; empty output usually means nothing is bound to it.
How do I block port 11434?
With UFW run `sudo ufw deny 11434/tcp`. With iptables run `sudo iptables -A INPUT -p tcp --dport 11434 -j DROP`. Persist the iptables rules with your distribution's netfilter-persistent or iptables-save tooling so they survive a reboot.
Is port 11434 safe to expose?
Ollama's local API has no authentication by default and can expose models and prompt execution. Do not publish it without a protected reverse proxy. Nevertheless, treat this port as sensitive. Restrict it to trusted networks or a VPN, require authentication and logging, and never expose it directly to the public internet without a hardened gateway in front.
Related ports
Primary data: IANA Service Name and Transport Protocol Port Number Registry.
Last reviewed 2026-10-30 · Methodology · About · Privacy