Implement and Troubleshoot Passive Interface

Passive interfaces controls the advertisement of routing information

Enables suppression of routing updates over some interfaces

Restricts outgoing advertisements with the exception of EIGRP

• EIGRP suppresses the exchange of Hellos
• Does not allow a neighbor to form

Enabled under the routing process

passive-interface

RIP: Prevent the interface from sending RIP advertisements

router rip
passive-interface [default]
no passive-interface [interface]

EIGRP: Supresses hello messages, preventing a neighbor relationship to form. Stops routing advertisements and incoming routing updates

router eigrp [as]
passive-interface [default]
no passive-interface [interface]

--

router eigrp [NAME]
address-family [ipv4/ipv6] unicast autonomous-system [as]
af-interface [interface]
[no] passive-interface

--

router eigrp EIGRP
 !
 address-family ipv4 unicast autonomous-system 1
 !
 af-interface default
 passive-interface
 exit-af-interface
 !
 af-interface GigabitEthernet0/1
 no passive-interface
 exit-af-interface
 !
 topology base
 exit-af-topology
 exit-address-family

OSPF: Setting an interface as passive disables the sending of routing updates on that interface, adjacencies will not be formed. The subnet will continue to be advertised to other interfaces.

router ospf [instance]
 passive-interface [default]
 no passive-interface [interface]

ISIS: Suppresses the sending of routing updates through the specified interface.

router isis
passive-interface [interface]
advertise-passive-only