I ran across this bit of material while learning about port access control lists:
PACLs have a few restrictions that vary from platform to platform. The following
are some of the most common restrictions:
• PACLs only support filtering incoming traffic on an interface (no outbound
filtering support).
• PACLs cannot filter Layer 2 control packets, such as CDP, VTP, DTP, PAgP,
UDLD, and STP.
• PACLs are supported only in hardware.
• PACLs do not support ACLs to filter IPv6, ARP, or Multiprotocol Label
Switching (MPLS) traffic.
1. Why don't PACLs support outbound filtering?
2. Why can't PACLs filter layer 2 control packets?
3. Why are PACLs only supported in hardware?
4. Why can't PACLs filter IPv6, ARP, or Multiprotocol Label
Switching (MPLS) traffic?
This post is loaded with questions. I greatly appreciate any input that you offer.
Jason
