Port 201AppleTalk Routing

AppleTalk Routing Maintenance (RTMP) port is used for maintaining and updating routing tables within AppleTalk networks. This service facilitates route discovery, management, and the dissemination of route updates ensuring seamless data delivery across interconnected Apple devices. Primarily, it helps routers to advertise their network reachability and adapt to topology changes dynamically..

transport
tcp · udp

2 transports registered

in transit
cleartext

payload readable on path

assignment
official

registered with iana

risk
4/10

caution

lookups
19,672

rank 129 of 993 · top 13%

Technical Details

what runs on :201

AppleTalk Routing Maintenance, leveraging the Routing Table Maintenance Protocol (RTMP), operates over port 201 to support dynamic routing across AppleTalk-based networks. RTMP enables routers to periodically broadcast their routing tables, allowing connected devices and routers to stay aware of the most efficient transmission paths within the AppleTalk ecosystem.

At a technical level, RTMP packets are transmitted every 10 seconds to inform neighboring routers about reachable networks and any changes in network topology. These packets carry detailed route information, including hop counts and network identifiers, promoting effective path recalculation whenever the network infrastructure changes.

Historically, AppleTalk played a critical role in enabling Mac-based connectivity for file sharing, printing, and service discovery. While its use has significantly declined in favor of IP-based protocols, understanding RTMP and its reliance on port 201 remains vital for backward compatibility and in specialized legacy systems that still employ AppleTalk routing.

Security Information

exposure of :201

risk score

4/ 10caution

worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.

network services averages 3.9 across 604 ports — this one sits 0.1 above.

in transit

cleartext

credentials and payloads are readable by anyone on path

assignment

official

registered with iana for this service — scanners fingerprint it by number

reachable over

tcp · udp

udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite

security overview

Common Vulnerabilities:

  • Lack of encryption makes RTMP communications susceptible to eavesdropping and route information tampering.
  • Man-in-the-middle attacks can manipulate routing tables, leading to traffic interception or denial of service.
  • Unauthorized access by attackers exploiting open port 201 can disrupt routing or gain insights into network topology.

Common Mitigations:

  • Disable AppleTalk and its routing services in environments where not explicitly required.
  • Employ strict access control lists (ACLs) and firewall rules to restrict incoming and outgoing traffic over port 201.
  • Segment legacy AppleTalk infrastructure from sensitive parts of the network using VLANs or separate subnets.
  • Monitor network activity for anomalous routing updates or suspicious access attempts aimed at port 201.
  • Transition legacy systems to modern, secure IP-based protocols whenever feasible.

the 8 most looked-up other ports in network services — 604 ports carry that label.

risk mix of the 8 listed

  • caution100%

0 of 8 encrypted