Understanding ACL Processing
This area helps you to accept ACL processing by answer entering and outbound ACLs, packet flow
rules, and guidelines for implementing ACLs.
Inbound ACL
Examine the pseudocode that follows to accept packet processing. When an entering ACL is activated on an
interface, the router checks the accustomed packet adjoin the ACL's statements for a match.
Code View:
if {a bout is found} then
if {the activity is to permit) then
{router continues to activity the packet}
else {the activity is to deny} then
{router discards the packet sending an ICMP Unreachable bulletin to the
source abode in the packet - bold this is not disabled}
endif
else {a bout is not found} then
{with the absence 'implicit deny' statement—the router discards the packet,
sending an ICMP Unreachable message}
endif