Technical Capacity for ASA
The PIX is an Internet Agreement firewall. It accepts and passes alone IP packets; all
others are dropped. It is account demography a moment to attending at the capacity of the protocols
to see what the PIX is attractive at and how it uses that information.
Internet Protocol
IP is an unreliable, routable packet commitment protocol. All upper-layer protocols use
IP to accelerate and accept packets. IP receives segments from the carriage layer, fragments
them into packets, and passes them to the arrangement layer.
The IP abode is a analytic abode assigned to anniversary bulge on a TCP/IP network.
IP acclamation is advised to acquiesce acquisition of packets beyond internetworks.
Since IP addresses are accessible to change or spoof, they should not be relied on to
provide identification in untrusted environments. As apparent in Figure 2.1, the
source and destination addresses are included in the IP header.
Let’s bound analysis the acceptation of key fields in Figure 2.1. Most are not
specifically allotment of the analysis exam, but it helps to put what the PIX does in
context:
The agreement constant indicates the upper-lev