Which type of firewall technology is considered the versatile and commonly used firewall
technology?

A.
static packet filter firewall

B.
application layer firewall

C.
stateful packet filter firewall

D.
proxy firewall

E.
adaptive layer firewall

Explanation:
http://www.cisco.com/en/US/prod/collateral/vpndevc/ps5708/ps5710/ps1018/
product_implementation_design_guide09186a00800fd670.html
Cisco IOS Firewall includes multiple security features:
• Cisco IOS Firewall stateful packet inspection provides true firewall capabilities to protect
networks against unauthorized traffic and control legitimate business-critical data.
• Authentication proxy controls access to hosts or networks based on user credentials stored in an
authentication, authorization, and accounting (AAA) server.
• Multi-VRF firewall offers firewall services on virtual routers with virtual routing and forwarding
(VRF), accommodating overlapping address space to provide multiple isolated private route
spaces with a full range of security services.
• Transparent firewall adds stateful inspection without time-consuming, disruptive IP addressing
modifications. • Application inspection controls application activity to provide granular policy
enforcement of application usage, protecting legitimate application protocols from rogue
applications and malicious activity.