• Port ACLs
    • Applies to layer 2 switchports
    • Apply ingress only
    • Filter transit traffic.
      • Traffic ingress on the VLAN/port
    • Could be IP or MAC based.
      • MAC ACLs only affect non-IP traffic.
  • Routed ACL
    • Same as PACL but only apply to L3 traffic.
    • Apply to L3 ports or SVIs.
    • Ingress or Egress unlike PACL
    • Can only filter using IPv4 standard/extended ACLs.

Routed ACL example:

Both switches are running SVI VLAN 10 attached to Gig0/0 as trunk. Each can ping each other’s IP address:

SW1 – 10.10.10.21/16
SW2 – 10.10.10.22/16

We’re going to apply an extended ACL to SVI VLAN 10 to block telnet traffic that is currently available from SW2 to SW1.

Now if we do a ‘debug ip icmp’ we’ll see that we’re administratively blocked when trying to telnet from R2 to R1.

  • VLAN ACL or VLAN MAP
    • Apply to an SVI
      • Effective for all ports in this VLAN
        • Access and Trunk Ports
      • May inspect both IP and non-IP traffic
        • Matching based on IP or MAC ACL
        • Configuring an IP/MAC entry activates implicit deny.
      • Good for impacting all future ports in VLAN.
      • Don’t use implicit deny
        • May block STP or ARP.
      • Be careful when filtering L2 traffic.
        • STP and ARP could be easily blocked.
      • Account for the fact that ALL transit traffic is affected.
        • Be careful when filtering transit VLANs.

VACL Example:

Now the access-map needs to be applied to VLAN 10.

Note – When doing a VLAN access map, ICMP will not respond saying the traffic was administratively dropped like it does with a normal ACL. It quietly drops the packet.

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