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6379 TCP
In-Memory Cache & Message Broker IANA Registered (Redis Cache)

Port 6379 — Redis In-Memory Data Store

Standard TCP listening port for Redis in-memory key-value cache, BullMQ background job queues, Celery task brokers, and pub/sub message brokers.

Default Protocol TCP / IP
Typical Localhost URL redis://localhost:6379
Default Process redis-server.exe
Primary Framework Redis / Dragonfly / KeyDB

1. What is Port 6379?

Port 6379 is the universally recognized port for Redis (Remote Dictionary Server). Redis is an ultra-low-latency in-memory data structure store used as a database, cache, streaming engine, and message broker.

Salvatore Sanfilippo (antirez), the creator of Redis, chose port 6379 because on a standard telephone keypad (ITU-T E.161), the digits 6-3-7-9 spell out the word **MERZ** — an inside joke named after Italian showgirl Alessia Merz whose name was used in discussions by his IRC circle.

2. How Port 6379 Works Under the Hood

1
Socket Creation & Binding

Process creates a Winsock socket (`AF_INET`/`AF_INET6`, `SOCK_STREAM`) and binds to local port 6379.

2
Kernel TCP Listener Table

Windows TCP/IP stack records the listening state in `MIB_TCPTABLE_OWNER_PID`.

3
Request Handling & Loopback Dispatch

Inbound HTTP/TCP traffic to `127.0.0.1:6379` is delivered directly through Windows loopback with zero physical NIC overhead.

Redis uses an asynchronous, single-threaded event loop driven by I/O multiplexing (`epoll` on Linux, `IOCP` / `select` on Windows ports): 1. `redis-server` opens TCP port 6379 in non-blocking mode. 2. Clients send commands encoded using the lightweight binary-safe **RESP** (REdis Serialization Protocol). 3. The server processes operations in-memory in microsecond timeframes without disk seek delays. 4. Optional persistence mechanisms (RDB snapshots and AOF logs) write to disk in the background while port 6379 continues serving client queries.

3. Common Conflicts & 'Could not connect to Redis at 127.0.0.1:6379: Connection refused'

⚠️ Common Error Message
Could not connect to Redis at 127.0.0.1:6379: Connection refused

Common Redis port issues on Windows: - Attempting to connect when Redis is running inside WSL2 without proper port-forwarding to the Windows host. - Leaving a Docker container binding `6379:6379` while trying to run a native Windows `redis-server.exe` build. - BullMQ or Celery worker processes attempting connection before Redis initialization completes, throwing unhandled connection refused exceptions.

💡 Pro Tip: Test responsiveness with `redis-cli ping` (should reply `PONG`). Keypad secret: 6379 spells 'MERZ' on phone keypads, referring to Italian singer Alessia Merz, an homage by Redis creator Salvatore Sanfilippo.

4. How to Find & Stop the Process on Port 6379

If port 6379 is locked by an orphaned process or background service, choose one of the following methods:

Terminal Commands (Manual) PortPeek (1-Click Instant)

PowerShell (Recommended):

Get-Process -Id (Get-NetTCPConnection -LocalPort 6379).OwningProcess | Stop-Process -Force

Classic CMD (Command Prompt):

for /f "tokens=5" %a in ('netstat -aon ^| findstr :6379') do taskkill /f /pid %a
PortPeek

Or simply use PortPeek

Never memorize netstat flags or parse PIDs again.

1. Press Win + Alt + P anywhere on Windows.
2. See Port 6379 with its owning process (redis-server.exe) and memory usage.
3. Click Stop Process to kill it instantly, or click the item to launch in your browser.
Download PortPeek (Free & Open Source)

5. Standards & Related Ports

Related Ports:

Port 5432Port 27017Port 11211

Official Specifications:

  • IANA Service Name and Transport Protocol Port Number Registry
  • RFC 6335, RESP (REdis Serialization Protocol)
  • Windows Sockets 2 (Winsock) API Documentation