Cisco ASA 5505 Configuration Manual page 435

Chapter 23 Configuring EIGRP
Customizing the EIGRP Hello Interval and Hold Time
The adaptive security appliance periodically sends hello packets to discover neighbors and to learn when
neighbors become unreachable or inoperative. By default, hello packets are sent every 5 seconds.
The hello packet advertises the adaptive security appliance hold time. The hold time indicates to EIGRP
neighbors the length of time the neighbor should consider the adaptive security appliance reachable. If
the neighbor does not receive a hello packet within the advertised hold time, then the adaptive security
appliance is considered unreachable. By default, the advertised hold time is 15 seconds (three times the
hello interval).
Both the hello interval and the advertised hold time are configured on a per-interface basis. We
recommend setting the hold time to be at minimum three times the hello interval.
To configure the hello interval and advertised hold time, perform the following steps:
In the main ASDM window, choose Configuration > Device Setup > Routing > EIGRP > Setup.
Step 1
The EIGRP Setup pane appears.
Check the Enable EIGRP routing check box.
Step 2
Click OK.
Step 3
Step 4 Choose Configuration > Device Setup > Routing > EIGRP > Interfaces.
The Interface pane appears and displays all of the EIGRP interface configurations.
Step 5 Double-click an interface entry or choose the entry and click Edit.
The Edit EIGRP Interface Entry dialog box appears.
Choose the EIGRP Autonomous system (AS) number from the drop-down list.
Step 6
This list is populated from system numbers that were set up when you enabled the EIGRP routing
process.
In the Hello Interval field, enter the interval between EIGRP hello packets sent on an interface.
Step 7
Valid values are from 1 to 65535 seconds. The default value is 5 seconds.
In the Hold Time field, specify the hold time, in seconds.
Step 8
Valid values are from 1 to 65535 seconds. The default value is 15 seconds.
Click OK.
Step 9
Disabling Automatic Route Summarization
Automatic route summarization is enabled by default. The EIGRP routing process summarizes on
network number boundaries. This can cause routing problems if you have noncontiguous networks.
For example, if you have a router with the networks 192.168.1.0, 192.168.2.0, and 192.168.3.0
connected to it, and those networks all participate in EIGRP, the EIGRP routing process creates the
summary address 192.168.0.0 for those routes. If an additional router is added to the network with the
networks 192.168.10.0 and 192.168.11.0, and those networks participate in EIGRP, they will also be
summarized as 192.168.0.0. To prevent the possibility of traffic being routed to the wrong location, you
should disable automatic route summarization on the routers creating the conflicting summary
addresses.
OL-20339-01
Cisco ASA 5500 Series Configuration Guide using ASDM
Customizing EIGRP
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