Port 376: NIP — The Amiga's Handshake

What This Port Does

Port 376 is officially assigned to NIP (Network Inquiry Protocol), part of Amiga Envoy—a peer-to-peer networking system developed by Commodore's Amiga Networking Group in the early 1990s.¹

NIP handles network discovery and inquiry for Amiga Envoy. When an Amiga computer running Envoy needs to find other Amigas on the network, it uses NIP on port 376 to ask: "Who else is out there?"²

The protocol operates over UDP (and is also registered for TCP), sending inquiry packets across the local network to discover available peers and services.³

The Story Behind Amiga Envoy

In the early 1990s, most networking required expensive servers and complex administration. Amiga Envoy took a different approach: true peer-to-peer networking where every Amiga was an equal participant.

Envoy let connected Amiga computers share:

• Hard disks and CD-ROMs (transparently, as if they were local)
• Printers (without a print server)
• Files with full Amiga metadata (file types, comments, icons)
• Notifications when files changed or disks were inserted⁴

Developed by software engineers Heinz Wrobel and Dale L. Larson, Envoy used Internet Protocol addressing but with Amiga-specific packet contents—different from Unix TCP/IP but sharing the same addressing scheme.⁵

It provided functionality similar to LAN Manager or AppleTalk, but designed specifically for Amigas talking to Amigas.

The Historical Significance

Port 376 appears in RFC 1700, published in October 1994. This RFC is historically significant: it was the last printed snapshot of "Assigned Numbers" before IANA moved the entire port registry online.⁶

For nearly two decades (1977-1994), the Internet Assigned Numbers Authority periodically published RFCs containing tables of protocol assignments. RFC 1700 was the final edition. In 2002, RFC 3232 officially obsoleted RFC 1700, noting that the registry had moved to a living database at iana.org.⁷

Port 376 exists in that last snapshot—a moment frozen between the RFC era and the database era.

Where Is Envoy Now?

Amiga Envoy represents a path not taken. While the Amiga platform faded in the mid-1990s, the peer-to-peer networking concepts Envoy embodied would resurface later in different forms: Windows file sharing, Bonjour/Zeroconf, and modern mesh networking.

Today, port 376 sits mostly silent. The Amiga networking community that once used it has largely moved on. But the port remains officially assigned, a permanent marker in the IANA registry commemorating Commodore's vision of computers as equal peers rather than clients and servers.

Current Status

Official Assignment: NIP (Amiga Envoy Network Inquiry Protocol)¹
Port Range: Well-known port (0-1023)
Protocols: UDP (primary), TCP (also registered)
Common Usage: Essentially none in modern networks
Security Notes: No known exploits; Amiga Envoy is no longer actively developed

If you see traffic on port 376 in a modern network, it's either:

• A vintage Amiga system still running Envoy (rare but possible)
• A misconfigured application mistakenly using this port
• Something worth investigating

How to Check What's Using Port 376

On Linux/macOS:

# See what's listening on port 376
sudo lsof -i :376

# Or using netstat
sudo netstat -tulpn | grep :376

On Windows:

# Check for processes using port 376
netstat -ano | findstr :376

Why Unassigned Ports Matter

Port 376 isn't unassigned—it has a clear, official purpose. But its story illustrates why the IANA registry preserves these assignments even when the original technology fades.

Ports are namespaces. Once assigned, they stay assigned to prevent conflicts. If IANA reclaimed port 376, a new service might use it, and then someone spinning up a vintage Amiga with Envoy would suddenly conflict with modern infrastructure.

The registry is archaeological. Every assigned port is a layer in the sediment—evidence of what we built, what we tried, what worked, and what didn't.

Port 376 is a fossil of peer-to-peer networking from an era when personal computers were just learning to be social.

Related Ports

• 137-139 — NetBIOS services (similar peer-to-peer file sharing for Windows)
• 548 — AFP (Apple Filing Protocol, AppleTalk's file sharing)
• 5353 — mDNS (modern zero-configuration networking, spiritual successor to protocols like NIP)