Intrusion Detection System and SMS controller with Snort using SMS Gateway on public networks. The need for an attack detection system that can assist administrators in monitoring the network, so that administrators can cope with threats quickly and the network can operate optimally again, the purpose of this study is to facilitate network administrators in preventing and detecting attacks. this has been tested against ping of death attacks, sql injection, sysflooding attacks and port scanning. From the results of testing the system that has been tested, the system has been able to detect and prevent it quickly via SMS controller integrated with gammu as an sms gateway, as for information sent to the network administrator in the form of attack alerts in real time via SMS, the result of attack detection in the form of 4 (four) types of information, namely attack time, attack type, destination IP, and source IP. Blocking attacks is done by sending blocking commands via an sms controller that is integrated with php scripts, bash scripting and iptables, blocking attacks successfully executed after the gammu server receives an SMS reply from the network administrator in an average period of 40 seconds.