Cisco Systems 3750E manual Creating a Numbered Extended ACL, 34-11

Chapter 34 Configuring Network Security with ACLs

Configuring IPv4 ACLs

The switch always rewrites the order of standard access lists so that entries with host matches and entries with matches having a don’t care mask of 0.0.0.0 are moved to the top of the list, above any entries with non-zero don’t care masks. Therefore, in show command output and in the configuration file, the ACEs do not necessarily appear in the order in which they were entered.

After creating a numbered standard IPv4 ACL, you can apply it to terminal lines (see the “Applying an IPv4 ACL to a Terminal Line” section on page 34-19), to interfaces (see the “Applying an IPv4 ACL to an Interface” section on page 34-20), or to VLANs (see the “Configuring VLAN Maps” section on page 34-29).

Creating a Numbered Extended ACL

Although standard ACLs use only source addresses for matching, you can use extended ACL source and destination addresses for matching operations and optional protocol type information for finer granularity of control. When you are creating ACEs in numbered extended access lists, remember that after you create the ACL, any additions are placed at the end of the list. You cannot reorder the list or selectively add or remove ACEs from a numbered list.

Some protocols also have specific parameters and keywords that apply to that protocol.

These IP protocols are supported (protocol keywords are in parentheses in bold):

Authentication Header Protocol (ahp), Enhanced Interior Gateway Routing Protocol (eigrp), Encapsulation Security Payload (esp), generic routing encapsulation (gre), Internet Control Message Protocol (icmp), Internet Group Management Protocol (igmp), any Interior Protocol (ip), IP in IP tunneling (ipinip), KA9Q NOS-compatible IP over IP tunneling (nos), Open Shortest Path First routing (ospf), Payload Compression Protocol (pcp), Protocol-Independent Multicast (pim), Transmission Control Protocol (tcp), or User Datagram Protocol (udp).

Note ICMP echo-reply cannot be filtered. All other ICMP codes or types can be filtered.

For more details on the specific keywords for each protocol, see these command references:

•Cisco IOS IP Command Reference, Volume 1 of 3: Addressing and Services, Release 12.2

•Cisco IOS IP Command Reference, Volume 2 of 3: Routing Protocols, Release 12.2

•Cisco IOS IP Command Reference, Volume 3 of 3: Multicast, Release 12.2

Note The switch does not support dynamic or reflexive access lists. It also does not support filtering based on the type of service (ToS) minimize-monetary-cost bit.

Supported parameters can be grouped into these categories: TCP, UDP, ICMP, IGMP, or other IP.

	Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-02		34-11