Basic EIGRP configuration

Configuring EIGRP

This section explains how to enable and restart the EIGRP process on your system. After enabling see the section, to learn how to customize the EIGRP process on your system.

•Enabling EIGRP

•Enabling EIGRP Stub Routing

•Restarting the EIGRP Process

Enabling EIGRP

You can only enable one EIGRP routing process on the ASA. To enable EIGRP, perform the following detailed steps.

Detailed Steps

	Command	Purpose
Step 1	router eigrp as-num Example: hostname(config)# router eigrp 2	This creates an EIGRP routing process, and the user enters router configuration mode for this EIGRP process. The as-num argument is the autonomous system number of the EIGRP routing process.
Step 2	network ip-addr [mask] Example: hostname(config)# router eigrp 2 hostname(config-router)# network 10.0.0.0 255.0.0.0	This step configure the interfaces and networks that participate in EIGRP routing. You can configure one or morenetwork statements with this command. Directly-connected and static networks that fall within the defined network are advertised by the ASA. Additionally, only interfaces with an IP address that fall within the defined network participate in the EIGRP routing process. If you have an interface that you do not want to participate in EIGRP routing, but that is attached to a network that you want advertised, see the section Configuring Interfaces in EIGRP.

Enabling EIGRP Stub Routing

You can enable, and configure the ASA as an EIGRP stub router. Stub routing decreases memory and processing requirements on the ASA. As a stub router, the ASA does not need to maintain a complete EIGRP routing table because it forwards all nonlocal traffic to a distribution router. Generally, the distribution router need not send anything more than a default route to the stub router.

Only specified routes are propagated from the stub router to the distribution router. As a stub router, the ASA responds to all queries for summaries, connected routes, redistributed static routes, external routes, and internal routes with the message "inaccessible." When the ASA is configured as a stub, it sends a special peer information packet to all neighboring routers to report its status as a stub router. Any neighbor that receives a packet informing it of the stub status will not query the stub router for any routes, and a router that has a stub peer will not query that peer. The stub router depends on the distribution router to send the proper updates to all peers.

To enable the ASA as an EIGRP stub routing process, perform the following steps:

Detailed Steps

	Command	Purpose
Step 1	router eigrp as-num Example: hostname(config)# router eigrp 2	This creates an EIGRP routing process, and the user enters router configuration mode for this EIGRP process. The as-num argument is the autonomous system number of the EIGRP routing process.
Step 2	network ip-addr [mask] Example: hostname(config)# router eigrp 2 hostname(config-router)# network 10.0.0.0 255.0.0.0	This step configure the interfaces and networks that participate in EIGRP routing. You can configure one or morenetwork statements with this command. Directly-connected and static networks that fall within the defined network are advertised by the ASA. Additionally, only interfaces with an IP address that fall within the defined network participate in the EIGRP routing process. If you have an interface that you do not want to participate in EIGRP routing, but that is attached to a network that you want advertised, see the section Configuring Interfaces for EIGRP.
Step 3	eigrp stub {receive-only | [connected] [redistributed] [static] [summary]} Example: hostname(config)# router eigrp 2 hostname(config-router)# network 10.0.0.0 255.0.0.0 hostname(config-router)# eigrp stub {receive-only | [connected] [redistributed] [static] [summary]}	This step configure the stub routing process. You must specify which networks are advertised by the stub routing process to the distribution router. Static and connected networks are not automatically redistributed into the stub routing process.

Restarting the EIGRP Process

To restart an EIGRP process, clear redistribution, or counters, enter the following command:

hostname(config)# clear eigrp pid {<1-65535> | neighbors | topology | events)}

Customizing EIGRP

This section describes how to customize the EIGRP routing, and includes the following topics:

•Configuring Interfaces for EIGRP

•Configuring the Summary Aggregate Addresses on Interfaces

•Changing the Interface Delay Value

•Enabling EIGRP Authentication on an Interface

•Defining an EIGRP Neighbor

•Redistributing Routes Into EIGRP

•Filtering Networks in EIGRP

•Customizing the EIGRP Hello Interval and Hold Time

•Disabling Automatic Route Summarization

•Disabling EIGRP Split Horizon

Configuring Interfaces for EIGRP

If you have an interface that you do not want to participate in EIGRP routing, but that is attached to a network that you want advertised, you can configure anetwork command that covers the network the interface is attached to, and use the passive-interface command to prevent that interface from sending or receiving EIGRP updates.

Detailed Steps

	Command	Purpose
Step 1	router eigrp as-num Example: hostname(config)# router eigrp 2	This creates an EIGRP routing process, and the user enters router configuration mode for this EIGRP process. The as-num argument is the autonomous system number of the EIGRP routing process.
Step 2	hostname(config-router)# network ip-addr [mask] Example: hostname(config)# router eigrp 2 hostname(config-router)# network 10.0.0.0 255.0.0.0	This step configure the interfaces and networks that participate in EIGRP routing. You can configure one or more network statements with this command. Directly-connected and static networks that fall within the defined network are advertised by the ASA. Additionally, only interfaces with an IP address that fall within the defined network participate in the EIGRP routing process. If you have an interface that you do not want to participate in EIGRP routing, but that is attached to a network that you want advertised, see the sectionConfiguring Interfaces for EIGRP.
Step 3	Do one of the following to customize an interface to participate in EIGRP routing:
	passive-interface {default | if-name} Example: hostname(config)# router eigrp 2 hostname(config-router)# network 10.0.0.0 255.0.0.0 hostname(config-router)# passive-interface {default}	This step prevents an interface from sending or receiving EIGRP routing message. Using the default keyword disables EIGRP routing updates on all interfaces. Specifying an interface name, as defined by the nameif command, disables EIGRP routing updates on the specified interface. You can have multiple passive-interfacecommands in your EIGRP router configuration.
	no default-information {in | out | WORD} Example: hostname(config)# router eigrp 2 hostname(config-router)# network 10.0.0.0 255.0.0.0 hostname(config-router)# no default-information {in | out | WORD}	This allows you to control the sending or receiving of candidate default route information. Configuring no default-information incauses the candidate default route bit to be blocked on received routes. Configuring no default-information out disables the setting of th edefault route bit in advertised routes.

Configuring the Summary Aggregate Addresses on Interfaces

You can configure a summary addresses on a per-interface basis. You need to manually define summary addresses if you want to create summary addresses that do not occur at a network number boundary or if you want to use summary addresses on a ASA with automatic route summarization disabled. If any more specific routes are in the routing table, EIGRP will advertise the summary address out the interface with a metric equal to the minimum of all more specific routes.

To create a summary address, perform the following steps:

Detailed Steps

	Command	Purpose
Step 1	interface phy_if Example: hostname(config)# interface phy_if	Enter interface configuration mode for the interface on which you are changing the delay value used by EIGRP.
Step 2	summary-address eigrp as-num address mask [distance] Example: hostname(config-if)# summary-address eigrp 2 address mask [20]	This step creates the summary address. By default, EIGRP summary addresses that you define have an administrative distance of 5. You can change this value by specifying the optionaldistance argument in the summary-addresscommand.