CCIE Pursuit Blog

April 9, 2008

Question Of The Day: 09 April, 2008

 Topic: IP Prefix Lists

Write a single line IP prefix list called “MY_SUBNETS” that will only allow the following subnets:

Click Here For Answer

Yesterday’s Question

Question Of The Day: 08 April, 2008 

Topic: IPv6

Router r1 is running OSPFv3:

r1#show ip interface brief | e ass
Interface                  IP-Address      OK? Method Status                Protocol
Serial1/0.12            YES NVRAM  up                    up     
Serial1/0.13            YES NVRAM  up                    up     
Loopback0                 YES NVRAM  up                    up     
Loopback1             YES NVRAM  up                    up     
Loopback2             YES NVRAM  up                    up     
Loopback3             YES NVRAM  up                    up   

r1#show ip interface brief
Serial1/0                  [up/up]
Serial1/0.12               [up/up]
Serial1/0.13               [up/up]
Loopback0                  [up/up]
Loopback1                  [up/up]
Loopback2                  [up/up]
Loopback3                  [up/up]

r1#show ip protocols summary
Index Process Name
0     connected
1     static

r1#show ipv6 protocols summary
Index Process Name
0      connected
1      static
2      ospf 100

r1#show ipv6 ospf interface
Serial1/0.12 is up, line protocol is up
  Link Local Address FE80::CE00:20FF:FE78:0, Interface ID 15
  Area 0, Process ID 100, Instance ID 0, Router ID ????
  Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    Hello due in 00:00:00
  Index 1/1/1, flood queue length 0
  Next 0x0(0)/0x0(0)/0x0(0)
  Last flood scan length is 0, maximum is 0
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 0, Adjacent neighbor count is 0
  Suppress hello for 0 neighbor(s)

r1#show run | sec ipv6 ospf|router-id
 ipv6 ospf 100 area 0

What is the OSPFv3 router-id of r1?


r1#sh ipv6 ospf data

            OSPFv3 Router with ID ( (Process ID 100)

                Router Link States (Area 0)

ADV Router      Age         Seq#        Fragment ID  Link count  Bits     642         0x80000001  0            0           None
—output truncated—

OSPFv3 will use an IPv4 address as its router-id.  The usual IPv4 router-id selection rules apply.  In this case is the highest IPv4 loopback address.  Since we did not manually specify an OSPFv3 router-id, this address will be used.


  1. […] Click Here For Answers […]

    Pingback by Question Of The Day: 08 April, 2008 « CCIE Pursuit — April 9, 2008 @ 6:13 am | Reply

  2. ip prefix-list MY_SUBNETS permit le 30

    uh.. i think. 😀

    Comment by f — April 9, 2008 @ 9:23 am | Reply

  3. […] Question Of The Day: 09 April, 2008  […]

    Pingback by Question Of The Day: 10 April, 2008 « CCIE Pursuit — April 10, 2008 @ 7:09 am | Reply

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