In day-to-day information security infrastructure, intrusion detection is indispensible. Signature based intrusion detection system mechanisms are often available in detecting many types of attacks. But this mechanism alone is not sufficient in many cases. Another intrusion detection method via K-means is employed for clustering and classifying the unlabelled data. IDS is a special embedded device or relied software package which process of monitoring the events occurring in a computer system or network (WLAN (Wi-Fi, WiMAX)) and LAN ((Ethernet, FDDI, ADSL, Token ring) based) and analyzing them for sign of possible incident which are violations or forthcoming threats of violations of computer security policies or standard security policies (i.e., DMA acts).