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To restrict egress trac, use an egress ACL. For example, when a direct operating system (DOS) attack trac is isolated to a specic
interface, you can apply an egress ACL to block the ow from the exiting the box, thus protecting downstream devices.
To create an egress ACL, use the ip access-group command in EXEC Privilege mode. The example shows viewing the conguration,
applying rules to the newly created access group, and viewing the access list.
Example of Applying ACL Rules to Egress Trac and Viewing ACL Conguration
To specify ingress, use the out keyword. Begin applying rules to the ACL with the ip access-list extended abcd command. To
view the access-list, use the
show command.
Dell(conf)#interface tengige 0/0
Dell(conf-if-te-0/0)#ip access-group abcd out
Dell(conf-if-te-0/0)#show config
!
TengigEthernet 0/0
no ip address
ip access-group abcd out
no shutdown
Dell(conf-if-te-0/0)#end
Dell#configure terminal
Dell(conf)#
ip access-list extended abcd
Dell(config-ext-nacl)#permit tcp any any
Dell(config-ext-nacl)#deny icmp any any
Dell(config-ext-nacl)#permit 1.1.1.2
Dell(config-ext-nacl)#end
Dell#show ip accounting access-list
!
Extended Ingress IP access list abcd on tengigEthernet 0/0
seq 5 permit tcp any any
seq 10 deny icmp any any
seq 15 permit 1.1.1.2
Applying Egress Layer 3 ACLs (Control-Plane)
By default, egress ACLs do not lter packets originated from the system.
For example, if you initiate a ping session from the system and apply an egress ACL to block this type of trac on the interface, the ACL
does not aect that ping trac. The Control Plane Egress Layer 3 ACL feature enhances IP reachability debugging by implementing
control-plane ACLs for CPU-generated and CPU-forwarded trac. Using permit rules with the count option, you can track on a per-ow
basis whether CPU-generated and CPU-forwarded packets were transmitted successfully.
1 Apply Egress ACLs to IPv4 system trac.
CONFIGURATION mode
ip control-plane [egress filter]
2 Apply Egress ACLs to IPv6 system trac.
CONFIGURATION mode
ipv6 control-plane [egress filter]
3 Create a Layer 3 ACL using permit rules with the count option to describe the desired CPU trac.
CONFIG-NACL mode
permit ip {source mask | any | host ip-address} {destination mask | any | host ip-address}
count
Dell Networking OS Behavior: Virtual router redundancy protocol (VRRP) hellos and internet group management protocol (IGMP) packets
are not aected when you enable egress ACL ltering for CPU trac. Packets the CPU sends with the source address as the VRRP virtual
IP address have the interface MAC address instead of VRRP virtual MAC address.
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Access Control Lists (ACLs)