Did you mean to connect to localhost:11211?

Did you mean to connect to: memcached://localhost:11211?

Port 11211 is for Memcached cache server connections. Use telnet, nc, or your application's cache client to connect.

💡 Pro Tip: Port 11211 is Memcached's default port. If you're getting connection errors, check if Memcached service is running and verify your connection configuration.

Quick Commands for Memcached Port 11211

Start Memcached server:
memcached -p 11211 -m 64
memcached -d -p 11211 -m 128 (daemon mode)
Connect to Memcached:
telnet localhost 11211
nc localhost 11211
echo "stats" | nc localhost 11211
Check Memcached status:
systemctl status memcached (Linux)
brew services list | grep memcached (Mac)
sc query memcached (Windows)
Find what's using port 11211:
lsof -i :11211 (Mac/Linux)
netstat -ano | findstr :11211 (Windows)

About Port 11211

Port 11211 is the default port for:

Common Memcached Connection Issues

"Connection refused" or "Connection timeout"

Memcached server is not running or not accessible:

Solutions:

  • Start Memcached: memcached -d -p 11211 -m 64
  • Check if service is running: systemctl status memcached
  • Verify port is not blocked by firewall
  • Check if another process is using port 11211
  • Restart Memcached service

"ERROR" or "CLIENT_ERROR" responses

Invalid commands or malformed requests to Memcached:

Solutions:

  • Check command syntax: help in telnet session
  • Verify key format and length
  • Check value size limits
  • Use proper command format
  • Test with simple commands first

"SERVER_ERROR" or "OUT_OF_MEMORY"

Memcached server is out of memory or experiencing issues:

Solutions:

  • Increase memory allocation: memcached -m 256
  • Check memory usage: echo "stats" | nc localhost 11211
  • Clear cache if needed: flush_all
  • Restart Memcached with more memory
  • Monitor memory usage patterns

⚡ Memcached Development Best Practices

Comprehensive guide for Memcached development and optimization

Installation & Configuration

  • brew install memcached - Install on Mac
  • apt-get install memcached - Install on Ubuntu
  • memcached -d -p 11211 -m 128 - Start server
  • Configure memory allocation and ports
  • Set up authentication if needed

Basic Commands

  • set key 0 3600 5 - Store value
  • get key - Retrieve value
  • delete key - Remove key
  • flush_all - Clear all data
  • stats - View statistics

Advanced Features

  • CAS (Check and Set) operations
  • Atomic increment/decrement
  • Multi-get operations
  • Compression for large values
  • LRU eviction policies

Performance Optimization

  • Key naming strategies
  • Memory allocation tuning
  • Connection pooling
  • Serialization optimization
  • Cache hit ratio monitoring

🔌 Client Integration

Integrating Memcached with various programming languages and frameworks

Python Integration

  • pip install python-memcached
  • import memcache
  • Connection pooling setup
  • Error handling and retries
  • Serialization with JSON

Node.js Integration

  • npm install memcached
  • const Memcached = require('memcached')
  • Cluster configuration
  • Promise-based operations
  • Connection management

PHP Integration

  • pecl install memcached
  • $memcached = new Memcached()
  • Session storage configuration
  • WordPress caching plugins
  • Laravel cache driver

Java Integration

  • spymemcached library
  • Spring Cache integration
  • Connection pool configuration
  • Serialization strategies
  • Cluster management

📊 Caching Strategies

Effective caching strategies and patterns for Memcached

Cache Patterns

  • Cache-Aside pattern
  • Write-Through caching
  • Write-Behind caching
  • Refresh-Ahead pattern
  • Cache-As-SoR pattern

Key Design

  • Consistent key naming
  • Namespace prefixes
  • Version-based keys
  • Hash-based distribution
  • Key expiration strategies

Data Management

  • Serialization formats
  • Compression for large data
  • Partial cache updates
  • Cache invalidation
  • Data consistency

Monitoring & Analytics

  • Hit/miss ratio tracking
  • Memory usage monitoring
  • Connection statistics
  • Performance metrics
  • Alerting and notifications

🚀 High Availability & Scaling

Building scalable and highly available Memcached deployments

Clustering & Distribution

Distributed Memcached setup:

  • Multiple Memcached instances
  • Consistent hashing for key distribution
  • Load balancing strategies
  • Failover mechanisms
  • Data replication approaches

Containerization

Docker and Kubernetes deployment:

  • Docker containers for Memcached
  • Kubernetes StatefulSets
  • Service discovery and load balancing
  • Persistent storage configuration
  • Health checks and monitoring

Cloud Integration

Cloud-based Memcached services:

  • AWS ElastiCache for Memcached
  • Google Cloud Memorystore
  • Azure Cache for Redis (alternative)
  • Managed service benefits
  • Auto-scaling capabilities

Performance Tuning

Optimization strategies:

  • Memory allocation optimization
  • Network configuration tuning
  • Concurrent connection limits
  • Eviction policy configuration
  • Monitoring and alerting

🔒 Performance & Security Best Practices

Optimize your Memcached deployment for better performance and security

Performance Optimization

  • Optimize memory allocation
  • Use connection pooling
  • Implement batch operations
  • Monitor cache hit ratios
  • Use appropriate TTL values

Security Measures

  • Network access control
  • Firewall configuration
  • Authentication if supported
  • Data encryption in transit
  • Regular security updates

Monitoring & Maintenance

  • Set up automated monitoring
  • Track performance metrics
  • Implement alerting
  • Regular maintenance tasks
  • Capacity planning

Development Workflow

  • Use version control for configs
  • Implement automated testing
  • Set up CI/CD pipelines
  • Code review processes
  • Documentation practices

Related Cache & Database Ports

📋 Port 11211 Development Summary

Port 11211 is the default port for Memcached, serving as a high-performance distributed memory caching system for web applications, databases, and APIs. It's essential for developers building scalable applications that require fast data access, session storage, and query result caching to improve performance and reduce database load.

Understanding Memcached configuration, caching strategies, client integration, and performance optimization is crucial for building high-performance applications. Port 11211 serves as the gateway to powerful caching features including distributed caching, session management, and performance acceleration that form the foundation of modern web applications and microservices.

Useful Memcached Resources

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