Zebra provides many very flexible filtering features. Filtering is used for both input and output of the routing information. Once filtering is defined, it can be applied in any direction.
| Menu |
|---|
| IP Access List |
| IP Prefix List |
| IP Community List |
| AS Path Access List |
Basic filtering is done by `access-list' as shown in the following
example.
ip prefix-list provides the most powerful prefix based filtering
mechanism. adding to access-list functionality, ip prefix-list
has prefix length range specification and sequential number specification. you
can add or delete prefix based filter to arbitrary point of prefix-list using
sequential number.
If there is no ip prefix-list is specified, it acts as permit. Once ip
prefix-list is defined, then there is no match is performed, default deny is
applied.
Command: access-list NAME deny IPV4-NETWORK
access-list filter deny 10.0.0.0/9
access-list filter permit 10.0.0.0/8
Command: ip prefix-list NAME seq NUMBER (permit|deny) [le LEN] [ge LEN]
You can create ip prefix-list using above commands.
seq seq NUMBER le le command specify prefix length. If
given prefix length is lesser than or equal to le prefix length. ge ge command specify prefix length. If
prefix length is greater than or equal to ge prefix length.
Menu
ip prefix-list description
ip prefix-list sequential number control
Showing ip prefix-list
Clear counter of ip prefix-list