The following examples show permit or deny filters for specific routes using the
le
and
ge
parameters, where x.x.x.x/x represents a
route prefix:
•
To deny only /8 prefixes, enter
deny x.x.x.x/x ge 8 le 8
.
•
To permit routes with the mask greater than /8 but less than /12, enter
permit x.x.x.x/x ge 8
.
•
To deny routes with a mask less than /24, enter
deny x.x.x.x/x le 24
.
•
To permit routes with a mask greater than /20, enter
permit x.x.x.x/x ge 20
.
The following rules apply to prefix lists:
•
A prefix list without any permit or deny filters allows all routes.
•
An “implicit deny” is assumed (that is, the route is dropped) for all route prefixes that do not match a permit or deny filter in a
configured prefix list.
•
After a route matches a filter, the filter’s action is applied. No additional filters are applied to the route.
Implementation Information
In Dell Networking OS, prefix lists are used in processing routes for routing protocols (for example, router information protocol [RIP],
open shortest path first [OSPF], and border gateway protocol [BGP]).
NOTE: It is important to know which protocol your system supports prior to implementing prefix-lists.
Configuration Task List for Prefix Lists
To configure a prefix list, use commands in PREFIX LIST, ROUTER RIP, ROUTER OSPF, and ROUTER BGP modes.
Create the prefix list in PREFIX LIST mode and assign that list to commands in ROUTER RIP, ROUTER OSPF and ROUTER BGP
modes.
The following list includes the configuration tasks for prefix lists, as described in the following sections.
•
Configuring a prefix list
•
Use a prefix list for route redistribution
For a complete listing of all commands related to prefix lists, refer to the
Dell Networking OS Command Line Interface Reference
Guide
.
Creating a Prefix List
To create a prefix list, use the following commands.
1.
Create a prefix list and assign it a unique name.
You are in PREFIX LIST mode.
CONFIGURATION mode
ip prefix-list
prefix-name
2.
Create a prefix list with a sequence number and a deny or permit action.
CONFIG-NPREFIXL mode
seq
sequence-number
{deny | permit}
ip-prefix
[ge
min-prefix-length
] [le
max-prefix-
length
]
The optional parameters are:
•
ge
min-prefix-length
: the minimum prefix length to match (from 0 to 32).
•
le
max-prefix-length
: the maximum prefix length to match (from 0 to 32).
Access Control Lists (ACLs)
129
Summary of Contents for S4048-ON
Page 1: ...Dell Configuration Guide for the S4048 ON System 9 9 0 0 ...
Page 146: ...Figure 14 BFD Three Way Handshake State Changes 146 Bidirectional Forwarding Detection BFD ...
Page 522: ...Figure 87 Configuring Interfaces for MSDP 522 Multicast Source Discovery Protocol MSDP ...
Page 523: ...Figure 88 Configuring OSPF and BGP for MSDP Multicast Source Discovery Protocol MSDP 523 ...
Page 528: ...Figure 91 MSDP Default Peer Scenario 1 528 Multicast Source Discovery Protocol MSDP ...
Page 529: ...Figure 92 MSDP Default Peer Scenario 2 Multicast Source Discovery Protocol MSDP 529 ...
Page 530: ...Figure 93 MSDP Default Peer Scenario 3 530 Multicast Source Discovery Protocol MSDP ...
Page 633: ...Policy based Routing PBR 633 ...
Page 777: ...Figure 119 Single and Double Tag TPID Match Service Provider Bridging 777 ...
Page 778: ...Figure 120 Single and Double Tag First byte TPID Match 778 Service Provider Bridging ...
