Port 153SGMP

_Simple Gateway Monitoring Protocol (SGMP) is an early network protocol designed to manage and monitor network gateways. It was a precursor to SNMP and enabled administrators to gather gateway status and control traffic-related parameters, providing basic insights into network health and performance._.

transport
udp

single transport

in transit
cleartext

payload readable on path

assignment
official

registered with iana

risk
5/10

caution

lookups
10,461

rank 425 of 993 · top 43%

Technical Details

what runs on :153

Simple Gateway Monitoring Protocol (SGMP) is a legacy protocol developed in the 1980s to facilitate simple management functions for network gateway devices such as routers. SGMP operates primarily over UDP port 153 and enables basic querying and configuration tasks related to network devices in an IP network environment.

SGMP allowed management systems to retrieve or modify status variables associated with gateways, such as interface status, throughput statistics, error counts, or uptime. The protocol employed simple command types such as GET and SET, using plaintext message exchanges to carry management data. Its simplicity provided a lightweight control plane suitable for early networks with limited resources.

Due to its limitations—including a lack of extensibility, rudimentary security, and minimal feature support—SGMP was superseded by the Simple Network Management Protocol (SNMP) which expanded functionality, standardized Management Information Bases (MIBs), and introduced improved transport and security mechanisms. Today, SGMP is largely obsolete, rarely deployed, and primarily encountered in historical network studies or legacy device support scenarios.

Security Information

exposure of :153

risk score

5/ 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 1.1 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

udp

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

security overview

Common Vulnerabilities:

  • Because SGMP transmits data in plaintext without authentication or encryption, it is vulnerable to eavesdropping and man-in-the-middle attacks.
  • Attackers can spoof management requests to manipulate gateway parameters or disrupt network traffic.
  • The protocol lacks mechanisms to ensure integrity, making it susceptible to tampering and injection attacks.
  • Legacy implementations may exhibit software bugs or buffer overflows due to lack of ongoing maintenance.

Common Mitigations:

  • Replace or disable SGMP services in favor of secure, modern protocols like SNMPv3.
  • Use network access controls to restrict SGMP traffic to trusted management hosts only.
  • Isolate management networks from general data traffic and enforce proper segmentation.
  • Employ monitoring and intrusion detection to identify anomalous management requests.
  • Where legacy SGMP must be supported, encapsulate traffic within secure tunnels (e.g., VPNs) to reduce risk.

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