Port 11211 is used by Memcached Cache Server (Memcached). Memcached is a distributed memory caching system used to speed up web applications by storing data in RAM.
What Does an Open Port 11211 Mean?
A Memcached server is exposed. Memcached has no authentication and was exploited for massive DDoS amplification attacks in 2018. Never expose Memcached to the internet.
This port should NOT be open to the public internet on typical systems. If you see it open, investigate immediately.
Security Risk Level
Critical Risk
How to Check if Port 11211 Is Open
Use the ExamineIP Port Scanner to check if port 11211 is open on any IP address from the public internet. Enter the target IP and select the relevant port preset.
How to Close Port 11211
- Stop the service using port 11211 if you no longer need it
- Add a firewall rule blocking inbound connections on port 11211
- Check your router for port forwarding rules that expose this port
- Run
netstat -ano | findstr :11211(Windows) to see which process is using it
Related Ports
Memcached is related to: {implode(‘, ‘, Array)}
Protect Your Open Ports
If you need services like remote access, use a VPN to create a private encrypted tunnel instead of exposing ports directly to the internet. A VPN also hides your real IP address so port scanners cannot identify your device. Try PureVPN or IPVanish.