Dual-Stack EIGRP Lab

Yet another routing protocol I played with in my lab. ;) This time: EIGRP, Enhanced Interior Gateway Routing Protocol, the proprietary distance-vector routing protocol developed by Cisco, which is now public available (RFC 7868). However, no third-party products in here but only Cisco routers. I am using named EIGRP for both Internet Protocols, IPv6 and legacy IP, along with MD5 authentication and redistribution from OSPF.


Three Cisco 2811 routers are involved here, IOS version 15.1(4)M12a. The overall lab is the following, while the EIGRP routers R1/2/3 are at the right-hand side:

Some details:

  • Named EIGRP, hence no EIGRP-related commands within the interfaces but all inside the router eigrp section.
  • I called the EIGRP Virtual-Instance “Bose” since I used my new Bose Noise-Cancelling-Headphones during the lab installation. ;)
  • Passive-interface default.
  • The point-to-point serial connection between R1 and R2 is a /127 for IPv6 and a /30 for IPv4. For the IPv6 addresses is used the :: and ::1 addresses, though NOT recommended in RFC 6164: “Addresses with all zeros in the rightmost 64 bits SHOULD NOT be assigned as unicast addresses, to avoid colliding with the Subnet-Router anycast address.”
  • Note that the IPv4 networks must have a “network” statement within the address-family, while the IPv6 networks mustn’t.
  • MD5 authentication via key-chain for both address-families. Use a Cisco password cracker for reverting the “type 7” hidden passphrase.
  • One stub router (R3, router-on-a-stick, multiple subinterfaces). The “eigrp stub connected summary” is used in both address-families.
  • This router (R3) also summarizes two of its /64 IPv6 prefixes to a /63 prefix, while two of its /24 IPv4 networks to a /23 address. Those commands are under the “af-interface fa0/0.127” section. Hence some additional route entries to “Null0” at R3, such as “ is a summary, 6d23h, Null0”.
  • R1 redistributes routes from OSPFv3 (IPv6) and OSPFv2 (legacy IP). Therefore I used the “default-metric …” command.
  • The additional “bandwidth 8000” commands in the interface sections are just for my monitoring system (Zabbix).


Following are the configuration commands for the three routers. I am listing the interfaces and the named EIGRP section but omitted any other details not needed here.







Show Commands

Here is a bunch of show commands gathered at R3, the rightmost router. First for IPv6:

And almost the same commands for legacy IP:


For more posts about routing/switching you can follow the Routing” or “Switching” categories concerning various firewall/router vendors, or the “Cisco Router“/”Cisco Switch” tags for posts related to Cisco stuff.

Featured image “Wegweiser” by Michael Riedel is licensed under CC BY 2.0.

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