Operating notes..................................................................................................................................... 128
Chapter 5 Routing Basics............................................................................130
Overview of IP routing............................................................................................................................130
Viewing the IP route table...................................................................................................................... 130
Increasing ARP age timeout (CLI)......................................................................................................... 130
Setting and viewing the arp-age value...................................................................................................131
Reconfiguring the router ID (optional)....................................................................................................132
Changing the router ID................................................................................................................132
Enabling proxy ARP...............................................................................................................................132
Enabling local proxy ARP............................................................................................................133
Configuring source MAC based ARP attack detection (ARP throttle)....................................................134
ARP throttle operation.................................................................................................................134
ip arp-throttle enable................................................................................................................... 134
ip arp-throttle remediation-mode................................................................................................. 134
ip arp-throttle aging-time............................................................................................................. 135
ip arp-throttle threshold............................................................................................................... 135
ip arp-throttle exclude-mac..........................................................................................................135
show ip arp-throttle......................................................................................................................136
Identifying blacklisted and restored clients..................................................................................137
Enabling forwarding of IP directed broadcasts (CLI)............................................................................. 138
Introduction to feature................................................................................................................. 138
CLI commands............................................................................................................................ 138
Configuration commands................................................................................................. 138
Show commands..............................................................................................................141
MIB..............................................................................................................................................143
Disabling the directed broadcasts............................................................................................... 143
Disabling replies to broadcast ping requests......................................................................................... 143
Disabling all ICMP unreachable messages.................................................................................144
Disabling ICMP redirects.............................................................................................................144
IP interfaces........................................................................................................................................... 144
IP tables and caches..............................................................................................................................144
ARP cache table......................................................................................................................... 144
ARP cache....................................................................................................................... 145
IP route table...............................................................................................................................145
Routing paths................................................................................................................... 145
Administrative distance.................................................................................................... 145
IP forwarding cache............................................................................................................................... 146
IP route exchange protocols.................................................................................................................. 146
IP global parameters for routing switches................................................................................... 146
IP interface parameters for routing switches...............................................................................149
Configuring IP parameters for routing switches..................................................................................... 150
Configuring IP addresses............................................................................................................150
Changing the router ID................................................................................................................150
Configuring ARP parameters...................................................................................................... 151
How ARP works............................................................................................................... 151
About enabling proxy ARP............................................................................................... 152
Proxy ARP and local proxy ARP behavior....................................................................... 152
Configuring forwarding parameters........................................................................................................153
Enabling forwarding of directed broadcasts................................................................................ 153
Configuring ICMP...................................................................................................................................153
Disabling ICMP messages.......................................................................................................... 153
Disabling ICMP destination unreachable messages...................................................................154
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