Wired Intelligent Edge (Campus Switching and Routing)

Configuration is applied on MAS 7.2 & above.

Prefix-list entry consists of:

• Sequence number
• Permit or deny
• Prefix: represents a subnet or a host
• Netmask
• ge and/or le (optional)

1. Prefix-list is configured to match an exact route or a  prefix range
2. Prefix-list is used for filtering OSPF routes from being added to the IP routing table

Notes
 

1. Only prefix-list can be used for distribute-list for filtering
2. Distribute-list is supported for inbound direction only
3. Only OSPF intra and inter area routes are filtered

Environment : Typical use case of running OSPF on network to filter the routes.

Network Topology : No Special network topology applied for this configuration for IP-Prefix-list on MAS 7.2

Prefix-list is configured in the IP-profile:
 
(ArubaS3500-48P) (config) #ip-profile
(ArubaS3500-48P) (ip-profile) #prefix-list PL1 seq 10 permit 1.1.1.0 255.255.255.0
(ArubaS3500-48P) (ip-profile) #prefix-list PL1 seq 20 permit 2.2.2.0 255.255.255.0 ge 27
(ArubaS3500-48P) (ip-profile) #prefix-list PL1 seq 30 permit 3.3.3.0 255.255.255.0 le 32 
(ArubaS3500-48P) (ip-profile) #prefix-list PL1 seq 40 permit 4.4.0.0 255.255.0.0 ge 24 le 32
 
The configured prefix-list can be applied as distribute-list for OSPF route filtering (inbound):
 
(ArubaS3500-48P) (Global OSPF profile) #distribute-list PL1

Above steps explains to configure IP-Prefix list.

Prefix-list can be verified by following CLI command
 
ArubaS3500-48P) #show ip-profile
ip-profile "default"
--------------------
Parameter            Value
---------            -----
Default Gateway      10.10.10.254
Import DHCP Gateway  Disabled
controller-ip        N/A
prefix-list          PL1 seq 10 permit 1.1.1.0 255.255.255.0
prefix-list          PL1 seq 10 permit 2.2.2.0 255.255.255.0 ge 27
prefix-list          PL1 seq 20 permit 3.3.3.0 255.255.255.0 le 32 
prefix-list          PL1 seq 30 permit 4.4.0.0 255.255.0.0 ge 24 le 32
 
 
Distribute-list can be verified by following CLI command
 
(ArubaS3500-48P) #show router ospf
Global OSPF profile "default"
-----------------------------
Parameter          Value
---------          -----
State              Enabled
Area               0.0.0.0
Area               0.0.0.1
Router-id          10.10.10.10
Distribute-list    PL1

Some of the useful commands to troubleshoot and verify is below.

show router ospf
show ip route
show ip interface brief
show running-config
Check for OSPF profile config.