Port 350 carries MATIP Type A—Mapping of Airline Traffic over Internet Protocol, Type A. This is the protocol that bridges 1960s-era airline reservation systems with the modern Internet.
What MATIP Does
MATIP wraps legacy airline protocols (IBM ALC and UNISYS UTS) in TCP/IP packets so they can travel across IP networks. Port 350 specifically handles Type A traffic: real-time query/response transactions for airline reservations and ticketing.1
Type A is designed for speed, not reliability. It's high priority, can be discarded if the network is congested, and has limited error protection. If a query gets lost, the user just sends it again. This is the traffic pattern of a terminal operator typing a reservation request and waiting for an immediate response.
Port 351 handles Type B traffic—email-style messaging that requires high reliability and delivery guarantees but doesn't need real-time speed.
Why This Port Exists
The airline industry built their reservation systems in the 1960s, well before OSI and SNA standards existed. By the late 1990s, thousands of airline offices around the world were still running these legacy terminals. Many airlines had no immediate plans to replace them.2
The problem: these systems spoke synchronous protocols designed for dedicated airline networks, not TCP/IP.
The solution: Alain Robert at SITA (Société Internationale de Télécommunications Aéronautiques) wrote RFC 2351 in May 1998, defining how to encapsulate airline-specific protocols over IP.3 Instead of ripping out decades of infrastructure, they wrapped it in TCP/IP and kept going.
How It Works
A legacy airline terminal in a ticket office connects to a router. The router encapsulates the proprietary airline protocol (P1024B or P1024C) inside MATIP packets and sends them over TCP to port 350 on the mainframe side. The mainframe unpacks them, processes the reservation, and sends the response back the same way.
The terminal doesn't know it's using the Internet. The mainframe doesn't care. MATIP is the translator between worlds separated by 30 years of technology evolution.
The Hidden Network
SITA operates a private IP network that connects most of the world's airlines. MATIP runs primarily on this network, not the public Internet. When you check in at an airport counter and the agent types into what looks like a DOS-era terminal, there's a decent chance that transaction is flowing through port 350 somewhere in the path.
Security Considerations
MATIP was designed for private airline networks, not hostile environments. The protocol has minimal built-in security—it predates modern threat models by decades.
Some security databases flag port 350 because malware has occasionally used unassigned or obscure ports for command and control. But MATIP itself isn't inherently dangerous; it's just old and assumes a trusted network.
If you see traffic on port 350 from an unexpected source, investigate. Legitimate MATIP traffic should only appear in airline or travel industry contexts.
The Truth About Legacy Systems
Port 350 is a monument to pragmatism. The airline industry could have spent billions replacing every terminal and retraining every agent. Instead, they wrote an RFC, assigned two ports, and kept the 1960s running on 1990s infrastructure.
This port is why legacy systems never die. They just get wrapped in another layer of protocol and continue serving travelers who have no idea how old the system booking their flight really is.
Related Ports
- Port 351 - MATIP Type B (reliable messaging with high protection)
Check What's Listening
To see if anything is listening on port 350:
Linux/Mac:
Windows:
Unless you work in airline systems or travel technology, you probably shouldn't see anything on this port.
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