>Верно ли про cef, и почему плохо указывать интерфейс ?исли интерфейс не multi-access, то не страшно. проблема с multi-access описана ниже:
http://www.cisco.com/en/US/tech/tk827/tk831/technologies_tech_note09186a00800cdf2e.shtml
Introduction
This document helps troubleshoot Cisco Express Forwarding (CEF) routing loops and sub-optimal routing caused by a valid cached Cisco Express Forwarding adjacency that points out the incorrect interface. An adjacency with an incorrect interface is created because of these reasons:
A static route points directly to a multi-access interface.
A valid Cisco Express Forwarding adjacency is built as a result of Proxy Address Resolution Protocol (ARP) replies.
Solution
Replace the floating static route that points directly to the Ethernet 0/0 with one that points to a next hop address.
R2(config)#no ip route 0.0.0.0 0.0.0.0 ethernet 0/0 10
R2(config)# ip route 0.0.0.0 0.0.0.0 192.168.12.1 10
When you have a static route that points to the next hop IP address instead of a multi-access interface Ethernet 0/0, it stops R2 from sending ARP requests for all destinations. The packets are routed and switched based on the next hop 192.168.12.1. Therefore, any ARP Cisco Express Forwarding entries and loops are avoided.