You just set up a security system in your network. In what kind of system would you find the following string of characters used as a rule within its configuration? alert tcp any any ->192.168.100.0/2

Firewall iptables rules use a different syntax structured around chains and targets, such as '-A INPUT -p tcp --dport 21 -j DROP', and do not use the alert keyword or msg option.

FTP servers control access through user authentication and configuration files, not through alert-based rule strings in this format.

Router ACLs and routing table configurations use vendor-specific command syntax entirely different from the Snort rule format shown.

The string 'alert tcp any any -> 192.168.100.0/24 21 (msg:"FTP on the network!";)' matches the exact Snort rule format consisting of an action keyword (alert), protocol (tcp), source and destination address-port pairs, and a parenthesized option block containing a human-readable message. Snort is a widely deployed open-source Intrusion Detection System that uses precisely this syntax to detect and alert on network activity matching defined patterns. No other device type listed uses this rule structure.