Users Guide

Access Control Lists 675
frame should also specify a source or destination MAC address wherever
possible. Likewise, MAC ACLs that specify a source MAC address should
specify an EtherType to avoid interfering with control-plane traffic.
In general, any rule that specifies matching on an upper-layer protocol field
should also include matching constraints for as many of the lower-layer as
where possible. For example, a rule to match packets directed to the well-
known UDP port number 22 (SSH) should also include matching constraints
on the IP protocol field (protocol=0x11 or UDP) and the source or
destination IP address. Table 19-3 lists commonly-used EtherTypes numbers:
Table 19-4 lists commonly-used IP protocol numbers:
Table 19-3. Common EtherType Numbers
EtherType Protocol
0x0800 Internet Protocol version 4 (IPv4)
0x0806 Address Resolution Protocol (ARP)
0x0842 Wake-on LAN Packet
0x8035 Reverse Address Resolution Protocol (RARP)
0x8100 VLAN tagged frame (IEEE 802.1Q)
0x86DD Internet Protocol version 6 (IPv6)
0x8808 MAC Control
0x8809 Slow Protocols (IEEE 802.3)
0x8870 Jumbo frames
0x888E EAP over LAN (EAPOL – 802.1x)
0x88CC Link Layer Discovery Protocol
0x8906 Fibre Channel over Ethernet
0x9100 Q in Q
Table 19-4. Common IP Protocol Numbers
IP Protocol Number Protocol
0x00 IPv6 Hop-by-hop option
0x01 ICMP