08-26-2008 01:37 AM - edited 03-06-2019 12:59 AM
Let's say I have 4 routers on the same network segment all running OSPF
but I do not want them all to become neighbors, just 2 and 2 is there a way to do this in OSPF ?
without using access lists on interface to block ospf or such methods
Solved! Go to Solution.
08-26-2008 02:55 AM
Hello Arni,
you can take advantage of OSPF authentication:
C and D will have both keys key1 and key2
A will have only key key1
B will have only key key2
so A and B shouldn't become neighbors for the key mismatch
Hope to help
Giuseppe
08-26-2008 01:58 AM
use "passive-interface" command !!!
or don't enable ospf on interfaces connecting other 2 routers.
08-26-2008 02:02 AM
dont think that will work
lets say I have routers A, B, C and D
A should neighor with C and D
B should neighbor with C and D
But A and B should not neighbor
and they are all on the same network
if I use passive interface on A or B they wont neighbor with C or D
:)
08-26-2008 02:20 AM
It depends, on which interfaces you are defining as passive-interface.
In this case define interface on Router B which is connecting to Router A as passive-interface.
HTH..
08-26-2008 02:23 AM
Ok as I said before they are all on the same network, so each device only has one interface to connect to the other 3
08-26-2008 02:34 AM
Are these routers are connected on LAN , having same subnet??
08-26-2008 02:55 AM
Hello Arni,
you can take advantage of OSPF authentication:
C and D will have both keys key1 and key2
A will have only key key1
B will have only key key2
so A and B shouldn't become neighbors for the key mismatch
Hope to help
Giuseppe
08-26-2008 03:23 AM
Passive interface would work on a interface . If you are saying that there is one interface to another router then if you don't want the particular router to be a ospf participant then then passive interface the router interface or don't setup ospf at all on the router is which case you will need default static routes pointing to the next hop and somewhere on a ospf router you will need statics pointing back to the boxes that are not running ospf for the subnets on that router. . Not sure why you want to do this.
08-26-2008 05:45 AM
If the routers are on the same subnet on the same broadcast network, the way i will do it is enable the network type "point-multipoint nonbroadcast" under the interface on the two routers and manually peer those routers with the neighbour [ip address] under the OSPF process. The routers will use unicast instead. No need for ACL or route-map or authentication.
Just beware that you will not have the DR/BDR functionality.
Francisco.
03-17-2015 06:34 AM
Thanks, this topic is 7 years old but this was the only/best solution I could find that would work so that I could have multiple OSPF devices on the same shared subnet then select which of these devices became neighbours.
Thanks
Carl Ratcliffe
Preston - Lancashire - England
02-15-2019 11:29 AM
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