Port 56Route Access Protocol

Route Access Protocol (RAP) is an early protocol primarily used for routing table maintenance and exchange within network infrastructures. It facilitates the distribution of routing information between routers, enabling dynamic network topology updates and helping routers adjust their forwarding decisions based on the latest route data..

transport
tcp · udp

2 transports registered

in transit
cleartext

payload readable on path

assignment
unofficial

used by convention

risk
4/10

caution

lookups
9,884

rank 480 of 993 · top 48%

1 other service is registered on port 56. compare all 2

Technical Details

what runs on :56

Route Access Protocol (RAP) was designed as a network control protocol that assists routers in exchanging routing information dynamically. It facilitates communication between routing devices, allowing them to share and synchronize their routing tables. RAP supports both connection-oriented (TCP) and connectionless (UDP) transport, offering flexibility in implementation depending on network requirements.

This protocol typically transmits data describing reachable networks, route metrics, and path information. Such updates allow routers to adapt to network topology changes, including the addition or removal of network devices or links. By automating the route update process, RAP helps reduce administrative overhead and ensures routing decisions remain efficient and effective.

While useful historically, RAP is largely considered obsolete today. More modern, scalable, and secure routing protocols — such as OSPF (Open Shortest Path First), IS-IS (Intermediate System to Intermediate System), and BGP (Border Gateway Protocol) — have superseded RAP in nearly all production environments.

Security Information

exposure of :56

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

unofficial

used by convention, not registered — what answers here varies by deployment

reachable over

tcp · udp

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

security overview

Common vulnerabilities associated with RAP include:

  • Lack of authentication and encryption, making routing updates susceptible to tampering or interception
  • Susceptibility to route injection attacks, leading to routing loops or blackholing of traffic
  • Exposure to denial-of-service (DoS) attacks by flooding routing requests or updates.

Mitigations often focus on:

  • Implementing strict access controls and filtering which devices can connect on port 56
  • Using secure, modern routing protocols that support authentication/encryption to replace RAP
  • Isolating routing infrastructure from untrusted networks, e.g., leveraging VPNs or management VLANs
  • Monitoring and logging routing updates and traffic on this port to identify anomalies.

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