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Configuring Network Security with ACLs
How to Configure Network Security with ACLs
MAC ACL to a Layer 2 Interface
After you create a MAC ACL, you can apply it to a Layer 2 interface to filter non-IP traffic coming in that interface. When
you apply the MAC ACL, consider these guidelines:
If you apply an ACL to a Layer 2 interface that is a member of a VLAN, the Layer 2 (port) ACL takes precedence over
an input Layer 3 ACL applied to the VLAN interface. Incoming packets received on the Layer 2 port are always filtered
by the port ACL.
You can apply no more than one IP access list and one MAC access list to the same Layer 2 interface. The IP access
list filters only IP packets, and the MAC access list filters non-IP packets.
A Layer 2 interface can have only one MAC access list. If you apply a MAC access list to a Layer 2 interface that has
a MAC ACL configured, the new ACL replaces the previously configured one.
How to Configure Network Security with ACLs
Creating a Numbered Standard ACL
Note:
When creating an ACL, remember that, by default, the end of the ACL contains an implicit
deny statement for all
packets that it did not find a match for before reaching the end. With standard access lists, if you omit the mask from an
associated IP host address ACL specification, 0.0.0.0 is assumed to be the mask.
Command
Purpose
1.
configure terminal
Enters global configuration mode.
2.
access-list
access-list-number
{
deny
|
permit
}
source
[
source-wildcard
] [
log
]
Defines a standard IPv4 access list by using a source address and
wildcard.
access-list-number
—Specifies a decimal number from 1 to 99 or
1300 to 1999.
deny
or
permit
—Specifies whether to deny or permit access if
conditions are matched.
source
—Specifies the source address of the network or host from
which the packet is being sent specified as:
The 32-bit quantity in dotted-decimal format.
The keyword
any
as an abbreviation for
source
and
source-wildcard
of 0.0.0.0 255.255.255.255. You do not
need to enter a source-wildcard.
The keyword
host
as an abbreviation for source and
source-wildcard of
source
0.0.0.0.
(Optional)
source-wildcard—
Applies wildcard bits to the source.
(Optional)
log
—Causes an informational logging message about
the packet that matches the entry to be sent to the console.
3.
end
Returns to privileged EXEC mode.
Summary of Contents for IE 4000
Page 12: ...8 Configuration Overview Default Settings After Initial Switch Configuration ...
Page 52: ...48 Configuring Interfaces Monitoring and Maintaining the Interfaces ...
Page 108: ...104 Configuring Switch Clusters Additional References ...
Page 128: ...124 Performing Switch Administration Additional References ...
Page 130: ...126 Configuring PTP ...
Page 140: ...136 Configuring CIP Additional References ...
Page 146: ...142 Configuring SDM Templates Configuration Examples for Configuring SDM Templates ...
Page 192: ...188 Configuring Switch Based Authentication Additional References ...
Page 244: ...240 Configuring IEEE 802 1x Port Based Authentication Additional References ...
Page 298: ...294 Configuring VLANs Additional References ...
Page 336: ...332 Configuring STP Additional References ...
Page 408: ...404 Configuring DHCP Additional References ...
Page 450: ...446 Configuring IGMP Snooping and MVR Additional References ...
Page 490: ...486 Configuring SPAN and RSPAN Additional References ...
Page 502: ...498 Configuring Layer 2 NAT ...
Page 770: ...766 Configuring IPv6 MLD Snooping Related Documents ...
Page 930: ...926 Configuring IP Unicast Routing Related Documents ...
Page 976: ...972 Configuring Cisco IOS IP SLAs Operations Additional References ...
Page 978: ...974 Dying Gasp ...
Page 990: ...986 Configuring Enhanced Object Tracking Monitoring Enhanced Object Tracking ...
Page 994: ...990 Configuring MODBUS TCP Displaying MODBUS TCP Information ...
Page 996: ...992 Ethernet CFM ...
Page 1066: ...1062 Using an SD Card SD Card Alarms ...