EIGRP Routing table is not Uptating

Answered Question
Mar 6th, 2008
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Hi All,


I am having problem in EIGRP. The routing table is not updating from neighboring router. The neighboring router is updating the routing table from their network.


Example.

Router A is my head office router and Router B is my branch office router RA is connected to RB through IPSEC VPN tunnel. Router B is not updating the routing table from RA. But RA is advertising RB. I am having problem with RB.


IN router B we put one default route like


Ip route 0.0.0.0 0.0.0.0 Router B VPN tunnel Interface


Please some one help me


Thanks a lot .


Correct Answer by Mohamed Sobair about 9 years 4 months ago

Hi,


Eigrp supports dynamic neighbor discovery.


Eigrp sends hellos and receives Ack through a multicast address 224.0.0.10, Those hello and Ack are not considered reliable because its not sent as unicast.


You make sure the interfaces are in common subnet. and have eigrp adjacent, then look for the IPsec tunneling issue.


Eigrp update has nothing to do with The tunnel.


HTH

Mohamed

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lamav Thu, 03/06/2008 - 11:43
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Is it an IPSec over GRE tunnel VPN? If not, RB will not receive EIGRP updates from RA because IPSec does not pass multicast traffic. EIGRP multicasts its updates to 224.0.0.10.


HTH


Victor

Jon Marshall Thu, 03/06/2008 - 11:50
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Hi


Following on from Victor's post, if that is the problem configure neighbor statements under your eigrp config which will make the updates unicast.


Jon

lamav Thu, 03/06/2008 - 11:55
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Good one, Jon. Forgot about that little trick :-)

Edison Ortiz Thu, 03/06/2008 - 12:38
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I'm echoing Victor's concerns on the GRE piece. You do need GRE on IPSec VPNs for non-IP traffic such as routing protocols to work.


IPSec is only for transporting IP encrypted traffic, EIGRP is a protocol on in itself.


If you can post more information, we should be able to help.


__


Edison.

Correct Answer
Mohamed Sobair Thu, 03/06/2008 - 12:43
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Hi,


Eigrp supports dynamic neighbor discovery.


Eigrp sends hellos and receives Ack through a multicast address 224.0.0.10, Those hello and Ack are not considered reliable because its not sent as unicast.


You make sure the interfaces are in common subnet. and have eigrp adjacent, then look for the IPsec tunneling issue.


Eigrp update has nothing to do with The tunnel.


HTH

Mohamed

thiru.vel10 Fri, 03/07/2008 - 18:37
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HI ALL,


Thanks for your support. The issue has fixed. There was a problem in Router A EIGRP Network. I have added one more one RB subnet in RA now it's working properly.


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