Configuring LDP inbound FEC filtering

Configure LDP inbound-FEC filtering to filter inbound label bindings on a MPLS router.

To enable LDP inbound FEC filtering,

In privileged EXEC mode, enter global configuration mode.
```
device# configure terminal
```
Configure the prefix list to be referenced by the LDP inbound-FEC filter.
```
device(config)# ip prefix-list list-abc permit 10.20.20.0/24
```
In this example, the list-abc prefix list allows the 10.20.20.0/24 route address.
Enable MPLS on the device.
```
device(config)# router mpls
```
Access LDP configuration mode.
```
device(config-router-mpls)# ldp
```
Configure the LDP inbound FEC filter.
```
device(config-router-mpls-ldp)# filter-fec-in list-abc
```
In this example, LDP accepts inbound FEC 10.20.20.0/24 through the list-abc prefix list and filter out all others FECs.

Note
When the prefix list referenced by the LDP inbound-FEC filter is configured or changed, all the existing in-bound FECs and received later are subject to the changed prefix list. There is a configurable delay between changing the prefix list and the changed prefix list taking effect on LDP FEC-filter configuration.

Verify the inbound FEC-filter configuration.

device(config-router-mpls-ldp)# do show running-config router mpls ldp
router mpls
 ldp
  ....
  filter-fec-in list-abc
 !
!

Example

The following example shows the previous steps to configure the LDP inbound-FEC filter.

device# configure terminal
device(config)# ip prefix-list list-abc permit 10.20.20.0/24
device(config)# router mpls
device(config-router-mpls)# ldp
device(config-router-mpls-ldp)# filter-fec-in list-abc