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TCP 11211

ProtocolTCP
Port11211
Labelsmemcached

Synopsis

  • Port 11211/TCP is the default port for Memcached, the distributed in-memory key-value cache daemon.
  • Real-world apps that use Memcached on 11211 include MediaWiki (e.g., Wikimedia deployments), WordPress via W3 Total Cache or Memcached plugins, and Drupal via the Memcache module.
  • OpenStack components (Keystone, Nova, Horizon) commonly use Memcached on TCP 11211 for token and session caching.
  • Managed cloud offerings expose Memcached on this port, including Amazon ElastiCache for Memcached and Google Cloud Memorystore for Memcached.
  • Facebook’s mcrouter and Twitter’s twemcache speak the Memcached protocol and route to or serve backends that typically listen on 11211.
  • Security note: exposed Memcached on 11211 (especially with UDP enabled) has been abused for reflection/amplification DDoS and can allow unauthorized access; best practice is to bind locally and firewall the port.

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