Title: ICND2 / 4. Troubleshooting

Q: What does Config-Register 0x2100 do?
A: Boots into ROMMON on next reload.

Q: What does Config-Register 0x2101 do?
A: Will use RXBOOT on the next reload. It's similar to the ROMMON, but not as bad.

Q: What command produced the following output?:
-#- --length-- -----date/time------ path
1     47438932 Nov 17 2015 05:43:06 +00:00 c1841-adventerprisek9-mz.151-4.M7.bin
16572416 bytes available (47439872 bytes used)
A: R1#show flash

Q: How would I change where or which file my router boots from?
A: R1(config)#boot system ?
  WORD   TFTP filename or URL
  flash  Boot from flash memory
  ftp    Boot from a server via ftp
  mop    Boot from a Decnet MOP server
  rcp    Boot from a server via rcp
  rom    Boot from rom
  tftp   Boot from a tftp server

Q: How would you configure your router to boot an image named "c1841-adventerprisek9-mz.151-4.M7.bin" from TFTP server 192.168.10.10 on the next reload?
A: R2(config)#boot system tftp://192.168.10.10/c1841-adventerprisek9-mz.151-4.M7.bin

How does the Cisco boot process work?

Q: What does SNMP do?
A: Grabs statistics from devices.

Q: What is an OID?
A: Object Identifier. Something that identifies individual attributes that contain properties on a device.

Q: What is an MIB?
A: Management Information Base, which is a whole bunch of OIDs put together.

Q: How would you enable IPv6 routing?
A: R1(config)#ipv6 unicast-routing

Q: How would you assign an IPv6 address to an interface?
A: R1(config)#int fa0/0
R1(config-if)#ipv6 address 2001:1::1/64

Q: How would you let all the PCs and devices on the network facing the interface know what the subnet prefix is?
A: R1(config-if)#ipv6 address 2001:1::1/64
R1(config-if)#ipv6 address autoconfig
After entering these commands, the computers should see this and then auto-generate their IPv6 address.

Q: How would you see a list of IPv6 addressing on all interfaces?
A: R1#show ipv6 interface brief

Q: In Windows, how would you see the IPv6 to MAC address mapping?
A: C:\Users\user>netsh interface ipv6 show neighbor
Interface 3: vEthernet (EXTERNAL(SHARED))
Internet Address                              Physical Address   Type
--------------------------------------------  -----------------  -----------
2601:601:8400:b659:6627:37ff:fe9a:7d21        64-27-37-9a-7d-21  Stale
fe80::1286:8cff:fe59:3cce                     10-86-8c-59-3c-ce  Reachable (Router)
fe80::594d:d286:ca98:7e1                      00-00-00-00-00-00  Unreachable
fe80::6627:37ff:fe9a:7d21                     64-27-37-9a-7d-21  Stale
fe80::e9f1:13e1:4927:a74b                     00-00-00-00-00-00  Unreachable
ff02::1                                       33-33-00-00-00-01  Permanent
ff02::2                                       33-33-00-00-00-02  Permanent
ff02::c                                       33-33-00-00-00-0c  Permanent
ff02::16                                      33-33-00-00-00-16  Permanent
ff02::fb                                      33-33-00-00-00-fb  Permanent
ff02::1:2                                     33-33-00-01-00-02  Permanent
ff02::1:3                                     33-33-00-01-00-03  Permanent

Q: In Cisco IOS, what command would you use to see an IPv6 to MAC address mapping?
A: Router#show ipv6 neigh
IPv6 Address                              Age Link-layer Addr State Interface
2001::2                                     0 0000.0C1B.AD01  REACH Fa0/0
2001::3                                     0 0001.9750.BC01  REACH Fa0/0
2001::4                                     0 0002.1757.E001  REACH Fa0/0
2001::5                                     0 0001.6325.A901  REACH Fa0/0

Q: How would you apply an access list in IPv6?
A: R1(config-if)#ipv6 traffic-filter ACL_NAME in||out

Q: What command would you issue to see all IPv6 access lists?
A: R2#show ipv6 access-list

Q: How would you enter IPv6 EIGRP router config?
A: R1(config)#ipv6 router eigrp <AS#>

Q: How would you configure EIGRP routing over IPv6?
A: R1(config)#ipv6 unicast-routing
R1(config)#ipv6 router EIGRP 1
R1(config-rtr)#no shutdown
R1(config-rtr)#int se0/0
R1(config-if)#ipv6 eigrp 1
You enable it on a per-interface basis as opposed to per-subnet

Q: How would you see all EIGRP over IPv6 neighbors?
A: R3#show ipv6 eigrp neighbor

Q: When using OSPFv3, what format is the RID in?
A: It is still in the IPv4 dotted decimal format

Q: How would you enable OSPF over IPv6?
A: R1(config)#ipv6 unicast-routing
R1(config)#ipv6 router ospf <processID>
R1(config-rtr)router-id 1.1.1.1
R1(config-rtr)interface se0/0
R1(config-if)#ipv6 ospf <processID> area 0
R1(config-if)#interface fa0/0
R1(config-if)#ipv6 ospf <processID) area 0

Q: The _________ command will configure the location of the configuration file. It must be followed by the copy run start command to be effective at next reboot.
A: R1(config)#boot ?
  bootstrap  Bootstrap image file
  config     Configuration file
  host       Router-specific config file
  network    Network-wide config file
  system     System image file

Q: How would you export your netflow info to a server?
A: R1(config)#ip flow-export destination <1.2.3.4> <unique.port.per.device>

Q: How would you set the direction of netflow you want to monitor?
A: R1(config-if)#ip flow ingress
R1(config-if)#ip flow egress