When a host transmits data across a network to another device, data is encapsulated with several headers and trailer.
Overview- OSI Reference Model- Encapsulation- Decapsulation- Connection Oriented Protocol-
Adaptive Security Appliance (ASA) Software is the core operating system for the Cisco ASA Family of security devices that provides users with highly secure access to data and network resources – anytime, anywhere, using any device
ASA Configuration & Management – Security Levels – Basic Security Policy – Access Control Lists – Routed / Transparent Mode
A firewall is a network security device that monitors incoming and outgoing network traffic and decides whether to allow or block specific traffic based on a defined set of security rules.
Security Threats – Stateless Firewall – Stateful firewall – Proxy Firewall – Application Firewall
Network address translation (NAT) allows a router to modify packets to allow for multiple devices to share a single public IP address.
Overview – Static NAT – Dynamic NAT – NAT Exemption – Policy NAT – Bidirectional NAT
The virtual firewall methodology enables a physical firewall to be partitioned into multiple standalone firewalls. In Cisco ASA, these virtual firewalls are known as security contexts. Objects are created in and used by the ASA in the place of an inline IP address in any given configuration
Context Configuration – System Configuration – Admin Context – Network / Service / Protocol Object
A Virtual Private Network is a mechanism for providing secure communication over the Internet.
Overview – Cryptography – VPN Phases – ISAKMP – IPSec – Encapsulating Security Payload – Authentication Header – Site to Site VPN – Site to Client VPN
The failover configuration requires two identical security appliances connected to each other through a dedicated and, optionally, a Stateful Failover link.
Active / Standby Failover – Active / Active Failover- Failover Links – Synchronization
Application filtering can provide greater control over traffic passing through the security appliance.
Protocol Inspection feature provides security appliance to do a deep packet inspection instead of passing the packet through the fast path.
Advanced Inspection HTTP / FTP / ICMP / DNS – URL Filtering – Applets Blocking