Questions tagged [eigrp]

Use this tag for questions about Cisco's EIGRP - Enhanced Interior Gateway Routing Protocol.

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Why Poison Reverse is used in EIGRP routing protocol?

EIGRP uses DUAL to achieve route-loop freedom. By design DUAL ensure no route-loop in the network. Then why does EIGRP use poison reverse UPDATE when there is a topology change? Is there any other ...
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Route-map to manipulate metric in EIGRP

I have following Setup R1 --- R2 --- R3 --- R4 --- R5 The same network is being advertised from R1 and R5. There is some difference in delay between the two paths R1-R2 and R4-R5. So the route from R1 ...
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Ramifications of turning off Spanning Tree for EIGRP network?

Ran into something I've never seen before in a production network I'm new to supporting and wanted to get the communities take on it. I have an EIGRP network that interconnects about 60 sites across a ...
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Why I can't ping in my network?

I have the following network: The following is my interface table: This is my PC IP address table: This is the configuration for Router ISP: ISP#show running-config Building configuration... ...
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how to configure EIGRP in my network?

I have the following network With the following routing table: Configuration of router 1 Building configuration... Current configuration : 1056 bytes ! version 15.1 no service timestamps log ...
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Port 88, would Kerberos conflict with EIGRP?

So from what I understand EIGRP works on top of the IP protocol layer 3 and uses RTP to multicast address 224.0.010 on PORT 88 But Kerberos also uses UDP PORT 88 for authentication. So would there be ...
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iBGP Question reagrding Distribute - List from EIGRP

So, I have the following topology. A-B | | C-D A-B-C-D are Routers. It doesn't matter what are the IP's of the interfaces. What matters is that I have 2 loopbacks for each router. 1.1.1.1 and 11.11....
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Eigrp flapping while using natting with route map

I have configured a topology which contains ip sla , route map , dual natting.It work perfect but when I used route map natting the eigrp become flapping and show the error is "retry limit ...
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Distribute list behavior on outgoing routing updates

i have this topology I'm studying route maps and pbr and distribution list , I advertise bunch of network address from R4 and R5 and R7 ,i managed to leverage route maps and distribute list to remove ...
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EIGRP : Feasibility Condition not satisfied

What happen if the Feasibility Condition not satisfied and we can not pick a feasible successor?
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Routing Protocols and sharing information

I am running multiple Protocols on different Routers as so: R1-RIPv2 EIGRP OSPF R2-OSPF and RIPv2 R3-RIPv2 and EIGRP R4-EIGRP and OSPF This is not a practical exercise, it is just to explore how ...
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How do I enable communication between hosts on two Intranets with different routing protocols

Having completed the Networking Essentials Course from Cisco Networking Academy, I've been practicing on Packet Tracer until I came across this scenario. Supposing we have two intranets, A and B. ...
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EIGRP advertising of routes for other networks behind us

Continuing my expedition in to trying to learn EIGRP and other routing techniques in GNS3, I now have another theoretical network, depicted below: Everything in the red area is a mystery. We do not ...
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EIGRP route redundancy in a ring topology

Within GNS3, I am attempting to configure five Cisco 3660 routers in a ring topology with EIGRP, as an early exercise to try and learn how to use EIGRP: These routers and virtual PCs are configured ...
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EIGRP to BGP to EIGRP

I would like to ask if it is possible to implement eigrp routing sent through bgp? I wanted to route from PC-1 to PC-2 using EIGRP. The connection between all of the three routers are through BGP ...
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If EIGRP is designed to work within same autonomous system, why it has concept of multiple ASN?

EIGRP is a CISCO proprietary protocol and a type of Interior Gateway Protocol, which replaced now obsolete Interior Gateway Routing Protocol. This protocol like every other interior routing protocol, ...
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Filter tagged route to downstream routers

I'd like to filter a redistributed route from EIGRP into OSPF to all routers in AREA2 and AREA34. I have tagged the route 10.90.100.0/24 with tag 90 at the Tampa router where its redistributed into ...
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How to check the route table on a neighboring router?

I have a router in a network, which use to show list of routes in the route table. Using the command- show ip eigrp topology I see some of the routes are removed after sometime, which were advertised ...
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EIGRP Holding Time Expire on VLAN Interfaces

I configure 2 Layer 3 Switches with VLANs and EIGRP route. But it always return a message like this : %DUAL-5-NBRCHANGE: IP-EIGRP 2019: Neighbor 192.168.20.253 (Vlan20) is down: holding time expired ...
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Why do we need EIGRP AS numbers when we have EIGRP RID?

I understand that the EIGRP routers need to have the same AS number to peer with each other. But why can't we just use EIGRP Router ID?
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How to ping from PC on EIGRP area to PC on OSPF area without middle router?

This is my topology. And I can send a package to every router and PC within the colored area, how can I ping from a PC on EIGRP area to a PC on the OSPF area? I heard about default route but I saw it ...
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EIGRP Adjacency Table

From Cisco IP Routing by Alex Zinin According to this figure Adjacency Table gets messages from DUAL module also.As far as I know, Adjacency Table is populated only because of Hello packets exchanged ...
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Packet Tracer 7.2.1 does not support eigrp for ipv6

I'm trying to enable eigrp for ipv6 in packet tracer but is seems to only have ospf and rip for ipv6. Is this a recent limitation?
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EIGRP unequal load balancing, variance command

Is correct to say that the value inserted in the variance command, lets say the value of "2" on a route that has a cost of, lets say "100", will unequally load balance all routes up to a cost of 200 ? ...
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EIGRP Auto-summary

One more question about EIGRP, EIGRP auto-summary what is the impact on the network ? i was reading about but it was not clear for me. And why is it a good Cisco practice to be disabled ? I am ...
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EIGRP metric claculation

I have a question regarding the EIGRP metric system. so if K1 is the Bandwidth and formula is : (K1 * BW + ((K2 * BW) / (256 - LOAD)) + K3 * DELAY ) * (K5 / (RELIABILITY + K4) Whats is BW and ...
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Why does EIGRP aim to be loop free?

As far as I understand: EIGRP is a routing protocol and handles IP packets. IP packets are outfitted with the TTL field and thus, do not loop indefinitely like layer 2 frames do. Why does EIGRP try ...
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Cisco numeric EIGRP routing IP summarizing and routing

I have 2 routers connected via Serial 0/0/0 both running EIGRP with an ASN of 65000, and i want to advertise and summarize the interfaces, being just my loopbacks, and set the loopbacks as passive. ...
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Is it possible to remove/block a EIGRP neighbors connection via Switch?

I have a 4 routers that connected each other via an multilayer switch. Is it possible to remove/block an EIGRP neighbors via Switch? For example, I have a topology like this : I wanted to remove ...
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672 views

EIGRP Routing Issues

I had an issues about EIGRP. But first, here's the topology : I've done EIGRP Routing, but it's kinda strange. PC0 -> PC1 is able to ping, PC3 -> PC2 is able to ping. But, I can't ping PC0 -> PC2, ...
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Why Static route (AD=150) and EIGRP route coexist under "show ip route"?

pic1 is topology pic2 is routing table. EIGRP is enabled with auto summary, why there is a static router (AD=150)?
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EIGRP authentication on GRE tunnel interface?

I want to implement authentication on EIGRP updates. Can I enable EIGRP authentication on a GRE tunnel interface instead of physical interface?
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Why does EIGRP have lower Administrative distance than OSPF?

I have given the following network diagram and been told that, Since EIGRP has a better (lower) administrative distance than OSPF, the router on the far left will use the EIGRP path and publish ...
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Filter routes based on interface

In EIGRP is there a way to filter routes entering from a specific interface? The intent is to protect the network core's routing table from receiving misconfigured or maliciously-inserted routes from ...
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417 views

Cannot see the differende between distance-vector and link-state

At link-state routing protocols each router advertises every link he knows about to the next router, which again advertises his links and so on until every router knows all links in his area. So every ...
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Will an EIGRP route be chosen over an OSPF route regardless of metrics?

I am sure this has been asked SOMEWHERE but I can't find it anywhere. Question is simple: Will R1 chose the EIGRP route to R4 over the OSPF route, even though the OSPF route is clearly the better ...
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EIGRP manual summarization prevent dual query

In EIGRP, manual summarization will prevent/ limit dual query. Is it true ? How can we limit the dual query by introducing manual summary ?
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BGP update source basics

I have the following test lab: The configuration of 'King' is: King#sho ip int bri Interface IP-Address OK? Method Status Protocol FastEthernet0/0 192....
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No passive-interface error

I'm trying to nest some EIGRP configurations on a router in GNS3. I'm trying to connect the EIGRP 2801 in SW01 to RTR-01 and EIGRP 2864 to RTR-02 when I do. When I put no passive-interface ...
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EIGRP neighbors discovering process

Quick question regarding EIGRP, as far I know, EIGRP has two tables: neighbors, and topology, and the router has its routing table obtained with DUAL algorithm applied to the topology table. ...
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EIGRP failover - how do i verify it happened?

I have 2 links to a destination and EIGRP was setup. The faster link is the successor and the slower link is the feasible successor. Switch1#show ip eigrp topology 192.168.1.0 EIGRP-IPv4 Topology ...
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How does Cisco router know the sum of delays in eigrp?

I know one can use sh ip route command example below, (r1) s2/0 -- s2/0 (r3) -- lo0 (r3) so the delay from r1 to r3 lo0 would be sum of delay on s2/0 and delay on lo0 on r3. it's easy for a ...
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1 vote
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c5915 DMVPN Spoke ISP Failover- Single Hub

I have a mobile application that utilizes cellular and satcom services to form a VPN connection to our hub. In the current configuration, failover works based on the ip hello-interval eigrp 1 15, ip ...
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Why does EIGRP not use Feasible Distance to determine the feasible successor

For EIGRP to determine a successor (best route), it uses the route with the lowest number of Feasible Distance(FD). And to determine the feasible successor (which is the backup route or the next best ...
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When do we need metric calculations when redistribute EIGRP to OSPF and vice versa?

I am a newbie, and I'm curious. When do we need to calculate metrics on redistributing EIGRP to OSPF and vice versa. My practice use Cisco, type a command redistribute EIGRP 1 metric ... I'm confused. ...
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How do OSPF and EIGRP deal with 2 exactly same routes?

If you refer this diagram, Will ospf and eigrp share the 10 network on the right to their neighbors? I am asking the question in two separate scenarios using a single protocol at a time and not ...
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2 votes
2 answers
1k views

Preventing Load balancing in EIGRP

In a recent project, I have been told to consider four Hubs (two in HQ, and two in DR), where each branch will have EIGRP neighborships with all four, as part of a DMVPN based WAN. I have tested this ...
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BGP problems, cannot ping

I'm beginner, and I have problems with BGP. I don't really understand why it doesn't work correctly. This is my topology: I need to ping from R8 to R10. This is the configuration of R8: ! ! ...
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A question about the router ID for EIGRP

If I configure a loopback interface and then set a router id by typing, eigrp router-id 10.0.0.1, for example, and the router protocol is EIGRP, what will be the accurate id for this router if the ID ...
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Handling multiple redundant Metro Ethernet circuits in one location

We have recently signed up for Metro Ethernet for our main campus and 8 branches. It's a "mesh" with the carrier providing a virtual layer-2 switch in the cloud. I have a Cisco router at each site ...
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