12-26-2018 10:29 PM - last edited on 03-02-2022 10:34 AM by Translator
Hi,
I wll be pleased to know if anyone guide me for how to STOP Eigrp, sending HELLO packets but keep on receiving?
I just tried to use commands as follow:
#access-list 1 deny any
#router eigrp 1
#distribute-list 1 out gig0/0 (I'm using gig0/0 as my outside interface to neighbor)
But RTR is still sending and receiving HELLO packets.
Regards,
MJM
Solved! Go to Solution.
01-01-2019 01:35 AM
Hello Muhammad,
All the best in 2019! :)
Regarding your initial question: No, it is not possible to stop EIGRP sending Hellos and yet keep the adjacency up. Think of this: EIGRP is an event-driven protocol, exchanging route updates only if there is a topology change. If the network is stable, there will be no updates whatsoever. However, this would also mean that a router would not be able to tell these two events apart:
Therefore, we absolutely rely on sending and receiving periodic Hello packets since they, among other purposes, allow the routers to know that they are still alive and running. We cannot stop the Hellos and expect EIGRP to still continue working as if nothing happened.
You are perhaps referencing the old trick using passive interfaces in RIP - a passive interface in RIP stopped sending out updates but still continued to process received updates. However, RIP was a timer-driven protocol, sending updates every 30 seconds even if there was no topology change, that's why this trick was possible. That being said, the behavior of passive interfaces in RIP was in fact quite cumbersome, and does not apply to any other routing protocol.
Feel welcome to ask further!
Best regards,
Peter
12-27-2018 12:17 AM - last edited on 03-02-2022 10:35 AM by Translator
The interface which dont want to be send or received the eigrp hello packets should make as passive interface example is as below
config t
router eigrp 1
passive-interface Gi0/0
end
Kindly rate for helpful post
12-27-2018 02:55 AM
Hi,
I want my EIGRP running router to only send HELLO packets but not want to receive hello packets at the same Time/Device.
With that my neighborship should remain established.
Please advice if any have the idea about?
Regards,
Anon
12-27-2018 03:43 AM - last edited on 03-02-2022 10:58 AM by Translator
Hi!
I don't know why you would want that but you could use an ACL on the interface denying packets from or for 224.0.0.10, you can also use the
eigrp neighbor
command too but that would disable dynamic discovery for EIGRP if I'm not wrong.
The
distribute list
command will only prevent the EIGRP process to send any subnets
ACL would prevent neighborship from forming and would be like this
ip access-list extended NOEIGRP
deny ip any 224.0.0.10
permit ip any any
interface gig 0/0
ip access-group NOEIGRP out - this one would be to prevent outgoing hello packets
ip access-group NOEIGRP in - this one would be to prevent incoming hello packets
Someone please correct me if I'm wrong.
The
neighbor
command needs to be applied in both peers to form a neighborship
router eigrp 1
neighbor 192.168.0.2 gig 0/0
12-28-2018 03:50 AM
12-31-2018 11:48 PM
Thanks for you Answer I can understand now what I did't focus on. Can you please tell me that is there any possibility to configure Eigrp device with condition as I've defines but peer remains UP(without neighborship termination).
Anon
01-01-2019 01:35 AM
Hello Muhammad,
All the best in 2019! :)
Regarding your initial question: No, it is not possible to stop EIGRP sending Hellos and yet keep the adjacency up. Think of this: EIGRP is an event-driven protocol, exchanging route updates only if there is a topology change. If the network is stable, there will be no updates whatsoever. However, this would also mean that a router would not be able to tell these two events apart:
Therefore, we absolutely rely on sending and receiving periodic Hello packets since they, among other purposes, allow the routers to know that they are still alive and running. We cannot stop the Hellos and expect EIGRP to still continue working as if nothing happened.
You are perhaps referencing the old trick using passive interfaces in RIP - a passive interface in RIP stopped sending out updates but still continued to process received updates. However, RIP was a timer-driven protocol, sending updates every 30 seconds even if there was no topology change, that's why this trick was possible. That being said, the behavior of passive interfaces in RIP was in fact quite cumbersome, and does not apply to any other routing protocol.
Feel welcome to ask further!
Best regards,
Peter
01-01-2019 07:39 AM
Peter has given an excellent explanation. I would add a comment to supplement it. Several of the suggestions involve using an access list to stop the advertisements. It is possible (but as Peter has explained it is not desirable) to use an access list to suppress receiving EIGRP hello packets. It is not possible to use an access list to suppress sending hello packets. The issue here is that an outbound acl will not filter packets generated by the router itself.
HTH
Rick
03-14-2019 01:59 AM
@Peter Paluch @Richard Burts Thank you for your corporation. Hopeful to get suitable solutions in case I found issues.
03-14-2019 04:45 AM
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