Filtering by known-unicast-only and unknown-unicast-only

Configure extended ACL rules to filter traffic by know-unicast-only and unknown-unicast-only.

This procedure configures filtering for known or unknown unicast traffic only. It is supported on Ingress ACL only on the L2 ratelimit profile. Implict deny will be applied on both known and unknown unicast traffic.

Enter configure to access global configuration mode.
```
device# configure
```
Enter the mac access-list extended command to create or access the ACL.
```
device(config)# mac access-list extended mac_ext22
```
Configure filtering on the ACL for known or unknown unicast traffic.
```
device(conf-macl-ext)# permit any any known-unicast-only
```

Apply the ACL to the appropriate interface.

device(config)# interface ethernet 0/1
device(conf-if-eth-0/1)# ip address mac_ext22 in