Dell S5148F-ON OS10 Enterprise Edition User Guide Release 10.3.2E-R2 - Page 372

Access Control Lists, IP ACLs

Page 372 highlights

6 Access Control Lists OS10 uses two types of access policies - hardware-based ACLs and software-based route-maps. Use an ACL to filter traffic and drop or forward matching packets. To redistribute routes that match configured criteria, use a route-map. ACLs ACLs are a filter containing criterion to match; for example, examine IP, TCP, or UDP packets, and an action to take such as forwarding or dropping packets at the NPU. ACLs permit or deny traffic based on MAC and/or IP addresses. The number of ACL entries is hardwaredependent. ACLs have only two actions - forward or drop. Route-maps not only permit or block redistributed routes but also modify information associated with the route when it is redistributed into another protocol. When a packet matches a filter, the device drops or forwards the packet based on the filter's specified action. If the packet does not match any of the filters in the ACL, the packet drops (implicit deny). ACL rules do not consume hardware resources until you apply the ACL to an interface. ACLs process in sequence. If a packet does not match the criterion in the first filter, the second filter applies. If you configured multiple hardware-based ACLs, filter rules apply on the packet content based on the priority NPU rule. Route maps Route-maps are software-based filtering in a routing protocol redistributing routes from one protocol to another and used in decision criterion in route advertisements. A route-map defines which of the routes from the specified routing protocol redistributed into the target routing process, see Route-maps. Route-maps with more than one match criterion, two or more matches within the same route-map sequence have different match commands. Matching a packet against this criterion is an AND operation. If no match is found in a route-map sequence, the process moves to the next route-map sequence until a match is found, or until there are no more sequences. When a match is found, the packet is forwarded and no additional route-map sequences process. If you include a continue clause in the route-map sequence, the next route-map sequence also processes after a match is found. The S5148F-ON platform has the following limitations: • ACL counter does not support byte count. • ACL rule does not look up the next header for IPv6 packets. • L2 Egress ACL does not work for unknown unicast traffic. • L2 User ACL has higher priority than the L3 User ACL. • You cannot modify or extend the hardware table for each ACL type. • In Ipv6 packets, only the protocol number of first header gets matched. • The egress Deny ACL entry does not block soft-forwarded packets and CPU-originated ICMP packets. IP ACLs An ACL filters packets based on the: • IP protocol number • Source and destination IP address 372 Access Control Lists

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Access Control Lists
OS10 uses two types of access policies — hardware-based ACLs and software-based route-maps. Use an ACL to
filter
traffic
and drop or
forward matching packets. To redistribute routes that match
configured
criteria, use a route-map.
ACLs
ACLs are a
filter
containing criterion to match; for example, examine IP, TCP, or UDP packets, and an action to take such as forwarding or
dropping packets at the NPU. ACLs permit or deny
traffic
based on MAC and/or IP addresses. The number of ACL entries is hardware-
dependent.
ACLs have only two actions — forward or drop. Route-maps not only permit or block redistributed routes but also modify information
associated with the route when it is redistributed into another protocol. When a packet matches a
filter,
the device drops or forwards the
packet based on the
filter’s
specified
action. If the packet does not match any of the
filters
in the ACL, the packet drops (implicit deny).
ACL rules do not consume hardware resources until you apply the ACL to an interface.
ACLs process in sequence. If a packet does not match the criterion in the
first
filter,
the second
filter
applies. If you
configured
multiple
hardware-based ACLs,
filter
rules apply on the packet content based on the priority NPU rule.
Route maps
Route-maps are software-based
filtering
in a routing protocol redistributing routes from one protocol to another and used in decision
criterion in route advertisements. A route-map
defines
which of the routes from the
specified
routing protocol redistributed into the target
routing process, see
Route-maps
.
Route-maps with more than one match criterion, two or more matches within the same route-map sequence have
different
match
commands. Matching a packet against this criterion is an AND operation. If no match is found in a route-map sequence, the process moves
to the next route-map sequence until a match is found, or until there are no more sequences. When a match is found, the packet is
forwarded and no additional route-map sequences process. If you include a continue clause in the route-map sequence, the next route-map
sequence also processes after a match is found.
The S5148F-ON platform has the following limitations:
ACL counter does not support byte count.
ACL rule does not look up the next header for IPv6 packets.
L2 Egress ACL does not work for unknown unicast
traffic.
L2 User ACL has higher priority than the L3 User ACL.
You cannot modify or extend the hardware table for each ACL type.
In Ipv6 packets, only the protocol number of
first
header gets matched.
The egress Deny ACL entry does not block soft-forwarded packets and CPU-originated ICMP packets.
IP ACLs
An ACL
filters
packets based on the:
IP protocol number
Source and destination IP address
6
372
Access Control Lists