Understanding DHS's role in cyber security

What is DHS's role in cyber security. DHS uses intrusion detection tools to monitor .gov network traffic for malicious activity and uses this resulting data to address cyber vulnerabilities. In addition, DHS issues bulletins and alerts that provide information on potential cyber threats. Last year, DHS issued more the 5,000 alerts and advisories, which it shared with various government, private sector, and critical infrastructure stakeholders; as well as the public.