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Port 1813RADIUS Accounting

RADIUS Accounting operates on port 1813 and is part of the Remote Authentication Dial-In User Service (RADIUS), primarily used for tracking usage and accounting purposes in network authentication scenarios. It helps network administrators manage resource consumption, billing, and audit trails by recording data usage, connection times, and user activity. Usually paired with RADIUS Authentication on port 1812, accounting ensures proper monitoring and management of network services..

inSecurityNetwork Services
transport
tcp · udp

2 transports registered

in transit
cleartext

payload readable on path

assignment
official

registered with iana

risk
4/10

caution

lookups
7,195

rank 711 of 993 · top 72%

Technical Details

what runs on :1813

RADIUS (Remote Authentication Dial-In User Service) is a standardized protocol used in network environments for authentication, authorization, and accounting of users who connect and use network services. Port 1813 specifically handles the accounting aspect, where user session data such as start and stop times, data transferred, and resources consumed is collected.

RADIUS Accounting is implemented through Accounting-Request and Accounting-Response message pairs transported over UDP or TCP on port 1813. These messages include information encoded in Attribute-Value Pairs (AVPs) that detail session metrics reported by the Network Access Server (NAS) to the RADIUS Accounting server. This enables service providers and enterprises to track resource utilization, plan capacity, and perform usage-based billing.

RADIUS Accounting supports both real-time reporting through interim updates and summary accounting upon session completion. The protocol is designed to be lightweight and compatible across diverse vendor solutions, making it broadly adopted in WiFi networks, ISPs, VPNs, and enterprise access solutions. As networks migrate to modern identity protocols, RADIUS remains a core component due to its simplicity and interoperability.

Security Information

exposure of :1813

risk score

4/ 10caution

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

security averages 3.8 across 216 ports — this one sits 0.2 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 affecting RADIUS Accounting include:

  • Susceptibility to packet interception and replay attacks due to the lack of encryption in the underlying protocol.
  • Man-in-the-middle attacks exploiting weak shared secret management between NAS devices and RADIUS servers.
  • Reflection and amplification attacks leveraging responses from RADIUS servers.
  • Unauthorized accounting data injection, leading to inaccurate billing or masking of malicious activities.

Security mitigations include:

  • Enabling IPsec or TLS tunnels around RADIUS communication (e.g., RadSec - RADIUS over TLS), to ensure confidentiality and integrity.
  • Enforcing strong shared secrets and rotating them regularly across devices.
  • Implementing strict access controls to allow only authorized NAS devices to communicate with RADIUS servers.
  • Monitoring traffic for anomalies and rate-limiting requests to prevent abuse.
  • Keeping RADIUS server software and NAS firmware updated to fix known vulnerabilities.

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all 216 in security →

the 8 most looked-up other ports in security — 216 ports carry that label.

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risk mix of the 8 listed

  • caution100%

3 of 8 encrypted