Port 11211 (Memcached)
Memcached in-memory cache.
- Transport
- TCP/UDP
- Internet exposure
- Never expose
Should not be reachable from the internet.
Security notes
- Memcached over UDP was abused in 2018 for record-breaking amplification DDoS attacks.
- No authentication by default; cached data can be read by anyone who connects.
When it shows up in your logs
Large UDP responses from 11211 leaving your network mean it is being used for amplification.