Port 208 sits in the well-known ports range with an unusual designation: officially assigned, but officially unused.
What Is Port 208?
Port 208 is registered with IANA under the service name at-8 (AppleTalk Unused) for both TCP and UDP protocols.1 It belongs to a block of eight ports (201-208) reserved for Apple's AppleTalk networking protocol suite. While its siblings had specific jobs — port 201 handled routing table maintenance (RTMP), port 202 managed name binding, port 204 provided echo services — port 208 was marked "Unused."2
It was reserved but never deployed. A spot held at the table that nobody sat in.
The AppleTalk Story
AppleTalk was Apple's proprietary networking protocol suite, released in 1985.3 Before Wi-Fi, before home networks were ubiquitous, AppleTalk allowed Macs to talk to each other and share printers without complex configuration. You plugged in a cable and it worked. For offices full of Macintosh computers in the late 1980s and early 1990s, AppleTalk was the invisible thread connecting everything.
The protocol suite needed multiple ports for its various services — routing, name resolution, file sharing. Ports 201 through 208 were allocated in the well-known range, managed by IANA's strict assignment procedures.4 These were system ports, the prestigious addresses that require IETF Review or IESG Approval to obtain.
Port 208 was part of that allocation, registered to Rob Chandhok from Carnegie Mellon University, who contributed to AppleTalk implementations and standardization efforts through the IETF.5 But unlike the other AppleTalk ports, 208 was explicitly designated as "Unused" — either reserved for future expansion that never came, or held as a buffer in the protocol's addressing scheme.
The Fall of AppleTalk
The rise of TCP/IP in the 1990s made proprietary networking protocols obsolete.6 The Internet's protocols became the universal standard. By the time Apple released Mac OS X 10.6 (Snow Leopard) in 2009, AppleTalk support was completely removed.7 The protocol suite that once connected every Mac in every office was gone.
But its port assignments remain. IANA's registry preserves them, a historical record of how the Internet's addressing system evolved. Port 208 stays marked "AppleTalk Unused" — reserved for a protocol that no longer exists, for a service that was never implemented.
What Range Does This Port Belong To?
Port 208 is in the well-known ports range (0-1023), also called system ports.8 These addresses are assigned by IANA through rigorous procedures requiring IETF Review or IESG Approval. Getting a well-known port is like getting a prestigious street address — it signals that a protocol is important enough to warrant permanent, universal recognition.
Once assigned, these ports typically aren't reallocated even if the original service disappears. IANA's policy requires that all unassigned ports in a range be exhausted before reassigning a previously used port number, and reasonable verification that the port is truly no longer in use.9 The well-known range still has unassigned numbers, so AppleTalk's ports remain exactly where they were allocated decades ago.
Current Use
Port 208 has no active official use. AppleTalk has been deprecated since 2009. Security databases have occasionally flagged this port in connection with malware, but that doesn't indicate a specific threat — merely that, like many unused ports, it has been opportunistically exploited by malicious software over the years.10
The port sits empty. It carries no legitimate traffic. No modern service listens on 208 by default.
Checking What's Listening
To see if anything is using port 208 on your system:
On Linux or Mac:
On Windows:
If something appears, it's not AppleTalk. It's either a modern application that chose an unused port number, or potentially something suspicious that warrants investigation.
Why Unassigned Ports Matter
The Internet runs on 65,535 possible port numbers per protocol (TCP and UDP). We need both assigned and unassigned ports. The assigned ones provide standards — everyone knows SSH lives at port 22, HTTPS at 443. The unassigned ones provide flexibility — applications can bind to ephemeral ports dynamically, services can claim unused addresses for new protocols.
Port 208 occupies a strange middle ground: assigned but unused. It's a reminder that protocol design involves planning for futures that may never arrive. AppleTalk's designers reserved eight ports, probably expecting the protocol suite to grow and evolve. It did grow, throughout the late 1980s and 1990s. But then it died, replaced by TCP/IP's universal standards.
The unused port remains as archaeological evidence. A fossil in the registry.
Related Ports
The AppleTalk protocol suite used these well-known ports:
- Port 201 (at-rtmp): AppleTalk Routing Table Maintenance Protocol
- Port 202 (at-nbp): AppleTalk Name Binding Protocol
- Port 204 (at-echo): AppleTalk Echo Protocol
- Port 206 (at-zis): AppleTalk Zone Information Protocol
- Port 208 (at-8): AppleTalk Unused
All are deprecated. All remain in the registry. Tombstones for a protocol suite that once seemed permanent but proved temporary, like everything else we build.
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