Hello,
Assume that you have three routers in a row - R1, R2 and R3.
R1 has a local network 10.0.1.0/24
R2 has a local network 10.0.2.0/24
R3 has a local network 10.0.3.0/24
The network between R1 and R2 is 10.0.12.0/24
The network between R2 and R3 is 10.0.23.0/24
The individual configuration would be as follows:
On R1:
router eigrp 64512
no auto-summary
network 10.0.1.0 0.0.0.255
network 10.0.12.0 0.0.0.255
On R2:
router eigrp 64512
no auto-summary
network 10.0.2.0 0.0.0.255
network 10.0.12.0 0.0.0.255
network 10.0.23.0 0.0.0.255
On R3:
router eigrp 64512
no auto-summary
network 10.0.3.0 0.0.0.255
network 10.0.23.0 0.0.0.255
The number after the "router eigrp" line is a process number. It is often called an autonomous system number but it is not in fact related to autonomous system numbering. Note that it must be identical on all routers that should communicate through EIGRP.
You then turn off automatic summarization in each EIGRP and add local networks to the EIGRP process. Note that each router has its own directly connected network added to the EIGRP configuration. The number "0.0.0.255" is a wildcard mask and it should represent the subnet mask of the network in an bit-inverted form. It might be confusing at first - don't bang your head around it but you can use the normal subnet mask format when entering the "network" commands. The router will recalculate the subnet mask to the wildcard format automatically here.
However, this is just a tiny fraction of EIGRP configuration. These forums cannot provide you with a complete tutorial about EIGRP, and configuring it in better detail also requires you to know the principles behind it. I suggest you read something about it - there are good books about EIGRP (notable the Routing TCP/IP, Vol.1, Jeff Doyle et al.) and also I suggest reading these documents on Cisco website:
http://www.cisco.com/en/US/tech/tk365/technologies_white_paper09186a0080094cb7.shtml
http://www.cisco.com/en/US/docs/ios/iproute/configuration/guide/irp_cfg_eigrp_ps6350_TSD_Products_Configuration_Guide_Chapter.html
Best regards,
Peter
