Core issue
The Policy Feature Card 1 (PFC1), the PFC2, and the first version of the PFC3 do not have Access Control List (ACL) counters for matches in the Ternary Content Addressable Memory (TCAM) that are denied or forwarded. Only packets that are switched by the Multilayer Switch Feature Card 2 (MSFC2) or switched at a rate of 10pps per VLAN, when the Internet Control Management Protocol (ICMP) Unreachable Destination Counters feature is disabled, are seen by the MSFC.
The show access-list command only displays statistics for traffic that matches the ACLs processed in the MSFC software. The show access-list command does not display statistics for traffic that matches an ACL supported in the PFC hardware.
Refer to Release Notes for Cisco IOS Release 12.1 E on the Catalyst 6000 and Cisco 7600 Supervisor Engine and MSFC for more information.
Resolution
In order to resolve this problem, issue the show tcam interface command. This command shows the ACL match counter in hardware.