tcpWatch is a specialized capability within SNM (Systems and Network Monitor), a lightweight, open-source IT infrastructure monitoring tool designed to track, graph, and alert on network resource parameters. What is SNM?
Systems and Network Monitor (SNM) acts as an easy-to-use frontend for Tobias Oetiker’s RRDtool. Unlike heavy enterprise monitoring platforms that require extensive database backends, SNM relies on simple XML configuration files and RRD (Round Robin Database) files. It runs continuously on Linux or Windows to collect metrics from connected network devices. The Role of tcpWatch
Within SNM, tcpWatch functions as a TCP port and connectivity monitoring module. Instead of relying on a standard ICMP ping (which only verifies that a machine’s network stack is responsive), tcpWatch acts as a TCP health monitor.
Port Availability Tracking: It tests whether specific application ports—such as HTTP (⁄443), FTP (21), SMTP (25), or Telnet (23)—are actively listening and accepting connections.
Performance Grids: It tracks the latency and response times required to complete a TCP handshake on those ports.
Status Alerting: If a designated number of sequential connection attempts fail or hit a timeout threshold, SNM triggers automated email alerts to system administrators.
RRD Tool Graphing: The connection speeds and failures captured by the module are passed into RRDtool, generating visual, historical trend graphs over time via a menu-driven web browser interface. Contrast with Independent “tcpwatch” Tools
It is worth noting that if you are looking at network utilities outside of the SNM platform, “tcpwatch” can refer to a couple of distinct, unrelated developer tools:
The tcpwatch Deadline Monitor: A Linux command-line tool that uses tcpdump and BPF filters to watch packet arrivals. If a packet does not arrive within a specified millisecond interval, it throws an outage log to syslog.
Python tcpwatch Proxies: Legacy Python-based forward/reverse proxy scripts historically used by developers to log, intercept, and analyze raw TCP data packets flowing between a client and a server.
Are you looking to configure the tcpWatch module inside an existing SNM deployment, or were you trying to use an independent command-line packet monitor? Let me know what you are building so I can provide the right configuration or commands! TCP Health Monitor – Broadcom TechDocs
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