Hello Ugo
The af-interface command is used to define user defaults to apply to EIGRP interfaces that belong to a particular address-family. The command can only be used with EIGRP’s named mode.
The command can be issued from the address-family configuration mode within the EIGRP router configuration. You can enter the configuration mode of all EIGRP interfaces on the router and issue commands for all of them, or you can choose individual interfaces to configure. For example, the following configuration sets all of the EIGRP interfaces to passive mode. Also, notice the options offered for the af-interface configuration mode command:
R1#configure terminal
R1(config)#router eigrp MyEIGRP_AS
R1(config-router)#address-family ipv4 vrf my_vrf autonomous-system 1
R1(config-router-af)#af-interface ?
Async Async interface
Auto-Template Auto-Template interface
BDI Bridge-Domain interface
BVI Bridge-Group Virtual Interface
CDMA-Ix CDMA Ix interface
CTunnel CTunnel interface
Dialer Dialer interface
GMPLS MPLS interface
GigabitEthernet GigabitEthernet IEEE 802.3z
Group-Async Async Group interface
LISP Locator/ID Separation Protocol Virtual Interface
LongReachEthernet Long-Reach Ethernet interface
Loopback Loopback interface
Lspvif LSP virtual interface
MFR Multilink Frame Relay bundle interface
Multilink Multilink-group interface
Tunnel Tunnel interface
Vif PGM Multicast Host interface
Virtual-PPP Virtual PPP interface
Virtual-Template Virtual Template interface
Virtual-TokenRing Virtual TokenRing
default Address-family default interface configuration
R1(config-router-af)#af-interface default
R1(config-router-af-interface)#passive-interface
R1(config-router-af-interface)#
The result of the default keyword is that all EIGRP interfaces associated with that address family have been configured to be passive. The af-interface command also allows you to specify specific interfaces for which to apply EIGRP configuration parameters. The following commands change the EIGRP hold time for the GigabitEthernet0/1 interface:
R1#configure terminal
R1(config)#router eigrp MyEIGRP_AS
R1(config-router)#address-family ipv4 vrf my_vrf autonomous-system 1
R1(config-router-af)#af-interface gigabitethernet 0/1
R1(config-router-af-interface)#hold-time 10
R1(config-router-af-interface)#
You can achieve the same thing by going to each EIGRP interface and applying whatever EIGRP command you like, however, this makes it easier to do so directly from the configuration mode of the address family.
You can find out more information bout this command at the following Cisco command reference:
I hope this has been helpful!
Laz