Port 11211

Q: What is port 11211?

Memcached distributed in-memory caching system Port 11211 is used by Memcached, a high-performance distributed in-memory object caching system used by Facebook, Wikipedia, and many large-scale websites to reduce database load. In 2018, exposed Memcached servers were weaponized in DDoS attacks with up to 51,000x amplification (via UDP), producing some of the largest DDoS attacks ever recorded. Always bind Memcached to localhost or trusted IPs only, and disable UDP if not needed.

Memcached

Memcached distributed in-memory caching system

Port

11211

Protocol

BOTH

Service

Memcached

Security

Dangerous

Full name: Memcached

What is port 11211?

Port 11211 is used by Memcached, a high-performance distributed in-memory object caching system used by Facebook, Wikipedia, and many large-scale websites to reduce database load. In 2018, exposed Memcached servers were weaponized in DDoS attacks with up to 51,000x amplification (via UDP), producing some of the largest DDoS attacks ever recorded. Always bind Memcached to localhost or trusted IPs only, and disable UDP if not needed.

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