EIGRP network command

[steven.crutchley]

My understanding of the network command within EIGRP is that when it is configured for any given prefixL

1) Neighborships are attempted on interfaces with IPs matching the neighbor command

2) Subnets on those interfaces are advertised

I am finding that static routes that point to interfaces for which the neighbor command has been used are being advertised as well. I am not sure if that this is correct though...

I have the following network:

R5 is acting like a host with the no ip routing and default-gateway 172.16.1.1 commands configured.

Because of this, on R1 I have set a static route pointing to 172.16.2.0/24 because it is no directly connected and R5 is not advertising it.  

Auto summarization is turned OFF on all routers.

When I type network 172.16.0.0 under eigrp configuration mode, other routers learn of 172.16.2.0/24 ... but why?

172.16.2.0/24 is not connected to R1. It is simply a static route that points out of fa1/0. Shouldn't I need to redistirbute static in order to get the other routers to learn of this static route?

The network command only advertises connected networks or interfaces and not static routes .... right? I mean otherwise the redistribute static command would be redundant...

Any help would be appreciated. Thanks in advance.

[Peter Paluch · Accepted solution]

Hi Steven,

When I type network 172.16.0.0 under eigrp configuration mode, other routers learn of 172.16.2.0/24 ... but why?
172.16.2.0/24 is not connected to R1. It is simply a static route that points out of fa1/0. Shouldn't I need to redistirbute static in order to get the other routers to learn of this static route? 

A static route configured with an egress interface without a next-hop IP address is considered by distance-vector routing protocols as a directly connected route. You may even see in R1's routing table that the network is reported as static, yet directly connected. Such static networks can be injected into distance-vector routing protocols in Cisco's implementation using the normal network command just like any other directly connected network. This is currently valid for both RIP and EIGRP. If you changed the static route that it uses a next hop IP address instead of egress interface, you would indeed need to use the redistribute static command.

Link-state routing protocols like OSPF or IS-IS do not behave this way. In these protocols, you always have to use redistribute static if you want to pick up static routes and propagate them.

Best regards,

Peter