Other EIGRP Properties
In EIGRP Operation there are some protocol characteristics that helps you better implementation. These characteristics are mentioned below.
By default EIGRP summarizes the classfull addresses. So generally “no auto-summary” command is used to avoid this situation.
Summary routes can also be produced manually. You can use this by “ip summary-address” command.
If you want to prevent one interface or all interfaces to receive EIGRP update and EIGRP hello packets , you can use “passive interface” command. By using this command, no update and hello packets coem to that interface anymore.
For example, with this command, you can prevent fa0/1 to receive update and hello packets like below.
You can also prevent all the interfaces to receive these packets and then you can open the ones you want. Below, firstly we prevent all interfaces and then allow fa0/5 and fa0/6.