11-08-2011 04:39 PM - edited 03-07-2019 03:17 AM
Hi all,
This command below
passive-interface command give additional information to RIP, that it can't send updates via this particular interface ---
As per my understanding is this if we have 2 routers that are directly connected with each other and we enable this command on the interface of one of
routers then that router will not send any RIP updates to other router right?
secondly if these 2 routers are point to point connection we can ping directly conencted interfaces IP of routers because they are directly connected even though there is no routing protocol running between these two right?
3rd thing when i run sh ip protocols on one of router it shows
Routing Protocol is "rip"
Sending updates every 30 seconds, next due in 1 seconds
Invalid after 180 seconds, hold down 180, flushed after 240
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Redistributing: rip
Default version control: send version 2, receive version 2
Interface Send Recv Triggered RIP Key-chain
FastEthernet0/0 2 2
Automatic network summarization is in effect
Maximum path: 4
Routing for Networks:
192.168.4.0
Routing Information Sources:
Gateway Distance Last Update
192.168.4.2 120 00:23:38 ****************************************************
here last update time keeps on incrementing but sh ip route does not show now that rip is running.
so this line means
Invalid after 180 seconds, hold down 180, flushed after 240
that after 240 secs router will flush the rip routes fron the routing table right?
but sh ip protocol will always show rip as routing protocol as we have config the rip and last update time will keep on incrementing right?
thanks
mahesh
Solved! Go to Solution.
11-08-2011 05:41 PM
Hi Mahesh,
From the config guide:
To control the set of interfaces with which you want to exchange routing updates, you can disable the sending of routing updates on specified interfaces by configuring the
passive-interface
here is the link:
http://www.cisco.com/en/US/docs/ios/12_0/np1/configuration/guide/1crip.html
Correct, you do not need a routing protocol. The interfaces are directly connected. Now, if for example you add a loopback address to each router, you need a routing protocol or static router to reach the opposite router's loopback address.
The reason the interfaces/IPs do not show up in the RIP routing table is because they are directly connected and directly connected routes have a lower admin distance (1) which is preferred over rip which is 120.
yes
HTH
11-09-2011 03:31 AM
Mahesk,
A interface configured as passive will still receive RIP updates on that interface and the interface subnet will still be advertised out even if that interface will not send updates to its directly connected neighbour.
RIP passive interface does not work like OSPF where the passive interface statement stops forming neighbour adjacencies over that link.
By default the full update is every 30 seconds.
the routing table will always prefer directly connected routes.
11-08-2011 05:41 PM
Hi Mahesh,
From the config guide:
To control the set of interfaces with which you want to exchange routing updates, you can disable the sending of routing updates on specified interfaces by configuring the
passive-interface
here is the link:
http://www.cisco.com/en/US/docs/ios/12_0/np1/configuration/guide/1crip.html
Correct, you do not need a routing protocol. The interfaces are directly connected. Now, if for example you add a loopback address to each router, you need a routing protocol or static router to reach the opposite router's loopback address.
The reason the interfaces/IPs do not show up in the RIP routing table is because they are directly connected and directly connected routes have a lower admin distance (1) which is preferred over rip which is 120.
yes
HTH
01-08-2016 01:21 PM
hi
if in case we have 3 router in that case if we will run this commend on the middle router than how the other router will able to communicate on the either side (how first and second router will communicate to each other ). as the middle router cant send the update and just can receive the updates.
11-09-2011 03:31 AM
Mahesk,
A interface configured as passive will still receive RIP updates on that interface and the interface subnet will still be advertised out even if that interface will not send updates to its directly connected neighbour.
RIP passive interface does not work like OSPF where the passive interface statement stops forming neighbour adjacencies over that link.
By default the full update is every 30 seconds.
the routing table will always prefer directly connected routes.
11-09-2011 06:52 PM
Hi,
thanks to both of you for very good explanation
Mahesh
12-16-2013 05:37 AM
PASSIVE INTERFACE COMMAND on RIP
hi...
1.passive-interface command will block sending update only..it will never block receiving updates..
ex:-R1 and R2 are connected to each other,R1 having loopbacks and R2 also having loopbacks both are connected to each other through serial interfaces are..S0/0 and S0/0 respectively, and the network is 192.168.12.0 R1 from(.1) and R2 from(.2) in which we want R1 will not send its update to R2.so the command is:
config#router rip
----------------------#passive-interface S0/0
after doing that it will complete block sending its update to R2.
2.if we want that R1 send its update to R2 but not send its update to all other loopback which are connected to behind R2,so the command is:
config#router rip
----------------------#passive-interface S0/0
----------------------#neighbour 192.168.12.2
by using neighbour command it send update to only its neighbour which is advertising into it like (192.168.12.2) and other will be block..
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