Reference Guide

Open Shortest Path First (OSPFv2 and OSPFv3) | 677
Enable passive interfaces
A passive interface is one that does not send or receive routing information. Enabling passive interface
suppresses routing updates on an interface. Although the passive interface will neither send nor receive
routing updates, the network on that interface will still be included in OSPF updates sent via other
interfaces.
Use the following command in the ROUTER OSPF mode to suppress the interface’s participation on an
OSPF interface. This command stops the router from sending updates on that interface.
To enable both receiving and sending routing updates, enter the
no passive-interface interface
command.
When you configure a passive interface, the
show ip ospf process-id interface command adds the words
“passive interface” to indicate that hello packets are not transmitted on that interface.
Note: If you enter the max-metric router-lsa command without an option (on-startup announce-time or
on-startup wait-for-bgp [wait-time]), the maximum metric of 65535 is always announced in LSAs sent by the
router.
Command Syntax Command Mode Usage
passive-interface
{default | interface}
CONFIG-ROUTER-
OSPF-id
Specify whether all or some of the interfaces will be passive.
Default enabled passive interfaces on ALL interfaces in the OSPF
process.
Entering the physical interface type, slot, and number enable passive
interface on only the identified interface.
• For a Gigabit Ethernet interface, enter the keyword
GigabitEthernet followed by the slot/port information (e.g.
passive-interface gi 2/1).
• For a port channel, enter the keyword port-channel followed by a
number from 1 to 255 for TeraScale and ExaScale (e.g.
passive-interface po 100)
• For a SONET interface, enter the keyword sonet followed by the
slot/port information (e.g. passive-interface so 2/2).
• For a 10-Gigabit Ethernet interface, enter the keyword
TenGigabitEthernet followed by the slot/port information (e.g.
passive-interface ten 2/3).
• For a VLAN, enter the keyword vlan followed by a number from 1
to 4094 (e.g. passive-interface vlan 2222).
E-Series ExaScale platforms support 4094 VLANs with FTOS
version 8.2.1.0 and later. Earlier ExaScale supports 2094
VLANS.
The default keyword sets all interfaces on this OSPF process as passive. The passive interface can
be removed from select interfaces using the no passive-interface interface command while
passive interface default is configured.
Command Syntax Command Mode Usage