White Papers

• Configuring Set Conditions
• Configure a Route Map for Route Redistribution
• Configure a Route Map for Route Tagging
• Continue Clause
• Logging of ACL Processes
• Guidelines for Configuring ACL Logging
• Configuring ACL Logging
• Flow-Based Monitoring Support for ACLs
• Enabling Flow-Based Monitoring
IP Access Control Lists (ACLs)
In Dell Networking switch/routers, you can create two different types of IP ACLs: standard or extended.
A standard ACL filters packets based on the source IP packet. An extended ACL filters traffic based on the following criteria:
● IP protocol number
● Source IP address
● Destination IP address
● Source TCP port number
● Destination TCP port number
● Source UDP port number
● Destination UDP port number
For more information about ACL options, refer to the Dell Networking OS Command Reference Guide.
For extended ACL, TCP, and UDP filters, you can match criteria on specific or ranges of TCP or UDP ports. For extended ACL
TCP filters, you can also match criteria on established TCP sessions.
When creating an access list, the sequence of the filters is important. You have a choice of assigning sequence numbers to
the filters as you enter them, or the Dell Networking operating system assigns numbers in the order the filters are created.
The sequence numbers are listed in the display output of the show config and show ip accounting access-list
commands.
Ingress and egress hot lock ACLs allow you to append or delete new rules into an existing ACL (already written into CAM)
without disrupting traffic flow. Existing entries in the CAM are shuffled to accommodate the new entries. Hot lock ACLs are
enabled by default and support both standard and extended ACLs.
NOTE: Hot lock ACLs are supported for Ingress ACLs only.
Implementing ACL on the Dell Networking OS
You can assign one IP ACL per interface. If you do not assign an IP ACL to an interface, it is not used by the software.
The number of entries allowed per ACL is hardware-dependent.
If counters are enabled on ACL rules that are already configured, those counters are reset when a new rule which is inserted
or prepended or appended requires a hardware shift in the flow table. Resetting the counters to 0 is transient as the proginal
counter values are retained after a few seconds. If there is no need to shift the flow in the hardware, the counters are not
affected. This is applicable to the following features:
● L2 Ingress Access list
● L2 Egress Access list
In the Dell EMC Networking OS versions prior to 9.13(0.0), the system does not install any of your ACL rules if the available
CAM space is lesser than what is required for your set of ACL rules. Effective with the Dell EMC Networking OS version
9.13(0.0), the system installs your ACL rules until all the allocated CAM memory is used. If there is no implicit permit in your rule,
the Dell EMC Networking OS ensures that an implicit deny is installed at the end of your rule. This behavior is applicable for IPv4
and IPv6 ingress and egress ACLs.
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Access Control Lists (ACLs)