These commands are for viewing and debugging the configuration
This command displays the current running configuration that is stored in RAM. With a few exceptions, all configuration commands that were used will be entered into the running-config and implemented immediately by the IOS.R2#show running-config Building configuration... Current configuration : 1493 bytes ! version 12.4 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname R2 ! boot-start-marker boot-end-marker ! enable secret 5 $1$7sIu$GqIQ4EcpGqjvKLiZFP5XG. ! no aaa new-model memory-size iomem 5 ! ! ip cef no ip domain lookup ip domain name home.ab ! ! interface Loopback0 ip address 172.16.0.1 255.255.255.224 ! interface Loopback1 ip address 172.16.0.33 255.255.255.224 ! interface FastEthernet0/0 no ip address shutdown duplex auto speed auto ! interface FastEthernet0/1 no ip address shutdown duplex auto speed auto ! interface Serial1/0 ip address 192.168.1.2 255.255.255.252 serial restart-delay 0 no fair-queue ! interface Serial1/1 no ip address shutdown serial restart-delay 0 ! interface Serial1/2 no ip address shutdown serial restart-delay 0 ! interface Serial1/3 no ip address shutdown serial restart-delay 0 ! ! router rip version 2 passive-interface Loopback0 passive-interface Loopback1 network 172.16.0.0 network 192.168.1.0 no auto-summary ! ip http server no ip http secure-server ip forward-protocol nd ! ! control-plane ! ! ! banner motd ^C This is a private machine. Unauthorized connections are logged and forbiden.^C ! line con 0 exec-timeout 0 0 password 7 060506324F41 logging synchronous login line aux 0 line vty 0 4 password 7 0822455D0A16 login line vty 5 1276 password 7 0822455D0A16 login ! ! end
This command displays the startup configuration file stored in NVRAM. This is the configuration that the router will use on the next reboot.
This configuration does not change unless the current running configuration is saved to NVRAM with the copy running-config startup-config command. Notice in the figure that the startup configuration and the running configuration are identical. They are identical because the running configuration has not changed since the last time it was saved. Also notice that the show startup-config command also displays how many bytes of NVRAM the saved configuration is using.
#show ip route
This command displays the routing table that the IOS is currently using to choose the best path to its destination networks. At this point, R1 only has routes for its directly connected networks via its own interfaces.R1#show ip route Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static routeGateway of last resort is 0.0.0.0 to network 0.0.0.017184.108.40.206/27 is subnetted, 2 subnets R 172.16.0.32 [120/1] via 192.168.1.2, 00:00:01, Serial1/0 R 172.16.0.0 [120/1] via 192.168.1.2, 00:00:01, Serial1/0 10.0.0.0/24 is subnetted, 1 subnets C 10.10.2.0 is directly connected, FastEthernet0/0 192.168.1.0/30 is subnetted, 1 subnets C 192.168.1.0 is directly connected, Serial1/0 S* 0.0.0.0/0 is directly connected, FastEthernet0/0
#show ip interface brief
This command displays abbreviated interface configuration information, including IP address and interface status. This command is a useful tool for troubleshooting and a quick way to determine the status of all router interfaces.R1#show ip interface brief Interface IP-Address OK? Method Status Protocol FastEthernet0/0 10.10.2.1 YES NVRAM up up FastEthernet0/1 unassigned YES NVRAM administratively down down Serial1/0 192.168.1.1 YES NVRAM up up Serial1/1 unassigned YES NVRAM administratively down down Serial1/2 unassigned YES NVRAM administratively down down Serial1/3 unassigned YES NVRAM administratively down down
This command displays all of the interface configuration parameters and statistics.R1#show interfaces FastEthernet0/0 is up, line protocol is up Hardware is AmdFE, address is cc00.0fc8.0000 (bia cc00.0fc8.0000) Internet address is 10.10.2.1/24 MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Full-duplex, 100Mb/s, 100BaseTX/FX ARP type: ARPA, ARP Timeout 04:00:00 Last input 00:02:48, output 00:00:05, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 375 packets input, 51726 bytes Received 373 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 watchdog 0 input packets with dribble condition detected 738 packets output, 73676 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 unknown protocol drops 0 babbles, 0 late collision, 0 deferred 0 lost carrier, 0 no carrier 0 output buffer failures, 0 output buffers swapped out
#show ip protocols
To display the parameters and current state of the active routing protocol process, use the show ip protocols command in EXEC mode.
The information displayed by the show ip protocols command is useful in debugging routing operations. Information in the Routing Information Sources field of the show ip protocols output can help you identify a router suspected of delivering bad routing information.
The following is sample output from the show ip protocols command that shows Routing Information Protocol (RIP) processes:
Routing Protocol is "rip" Sending updates every 30 seconds, next due in 2 seconds Invalid after 180 seconds, hold down 180, flushed after 240 Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Redistributing: rip Default version control: send version 2, receive version 2 Interface Send Recv Key-chain Ethernet0 2 2 trees Fddi0 2 2 Routing for Networks: 172.19.0.0 10.2.0.0 10.3.0.0 Routing Information Sources: Gateway Distance Last Update Distance: (default is 120)