Category: CCNA Study Guide

Command Passive-Interface Default Use This command prevents EIGRP from forming adjacencies on all interfaces on the router. Using no passive-interface default will allow EIGRP communication. Syntax Router(config-router)#passive-interface default Example In this example, we will use passive-interface default to block all EIGRP adjacencies. Afterwards, we will allow communication through R2’s fa0/0. R2(config)#do show …

Command Distribute-List Use Allows you to filter routes from the routing table. For CCNA purposes, this is usually done through access lists. Syntax Router(config-router)#distribute-list <list> <in/out> OR Router(config-router)#distribute-list <list> <in/out> <interface> Options <list> Access list <in/out> Whether the router is receiving or sending the route Example In this …

Command No Auto-Summary Use Disables EIGRP’s default behavior to advertise networks at their classful boundary. Syntax Router(config-router)#no auto-summary Example In this example, we will disable auto-summary in the EIGRP process and observe the difference. First we will enable EIGRP on all routers for all links. R1(config)#router eigrp 100 …

Command Neighbor Use This command tells RIP to communicate with unicast updates to a specific neighbor. This is usually used with the passive-interface default command to prevent all other RIP communication. Syntax Router(config-router)#neighbor <ip address> Example In this example, we will configure R4 to send its updates to R3 using …

Command Offset-List Use This command allows you to modify the metric of a route on the routing table. Syntax Router(config-router)#offset-list <list> <in or out> <offset> <interface> Options <list> = 0 All networks <list> = 1-99, 1300 – 1999 Standard accses list <list> = Name Named access list <in> …

Command Passive-Interface Default Use This command disables RIP for all interfaces on the router. Syntax Router(config-router)#passive-interface default Example First, here are the route tables for all routers with no passive-interface default. R2#conf t Enter configuration commands, one per line. End with CNTL/Z. R2(config)#router rip R2(config-router)#no passive-interface default R1 route …

Command Network Use Specifies which interfaces RIP will run on. Syntax Router(config-router)#network <ip address> Example In this example, RIP is enabled for all interfaces on R2. R2#conf t Enter configuration commands, one per line. End with CNTL/Z. R2(config)#router rip R2(config-router)#network 10.1.1.2 R2(config-router)#network 10.2.2.2 R2(config-router)#network 2.2.2.2 Here, the running …

Command Timers Use Changes the RIP timers associated with RIP on the router. Syntax Router(config-router)#timers basic <update interval> <invalid> <holddown> <flush> <sleep time> Options <update interval> Time between route updates <invalid> Time interval that determines that a route is down <holddown> Route is no longer used but is …

Command Distribute-List Use Allows you to filter routes from the routing table. For CCNA purposes, usually this is done through access lists. Syntax Router(config-router)#distribute-list <list> <in/out> OR Router(config-router)#distribute-list <list> <in/out> <interface> Options <list> Access list <in/out> Whether the router is receiving or sending the route Example In this …

Command Validate-Update-Source Use This command is enabled by default. When enabled, RIP will only allow routes received on the same subnet. Syntax Router(config-router)#validate-update-source Example In this example, here’s what happens when no validate-update-source is enabled on R2. First, the IP of int fa0/0 on R2 is changed to 10.5.5.2, which …