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Distribute List

July 26th, 2017 in ROUTE 300-101 Go to comments

Question 1

Question 2

Explanation

A distribute list is used to filter routing updates either coming to or leaving from our router. In this case, the “out” keyword specifies we want to filter traffic leaving from our router. Access-list 2 indicates only routing update for network 1.2.3.0/24 is allowed (notice that every access-list always has an implicit “deny all” at the end).

Question 3

Explanation

With EIGRP or OSPF running on a network, the “passive-interface” command stops both outgoing and incoming routing update (while RIP passive interface command will prevent RIP updates from being sent on the interface). Therefore “passive-interface” is not a good answer.

Distribute-list is used to control routing updates either coming to your router or leaving from our router so this is a better choice. For example we can prevent routing updates from sending out Fa0/0 with this command:

Router(config)#access-list 2 deny any
Router(config)#router ospf 1
Router(config-router)#distribute-list 2 out fa0/0
Comments
  1. Eminems
    August 1st, 2016

    @BK
    for me E should be right because there’s no permit any in the access-list so it will block anything aside from the permitted IP.
    This is just a tricky question.

  2. cls
    August 13th, 2016

    Here is the reason for Q1

    A. Traffic is not blocked by ACL. It is permitted outbound. There is no inbound ACL so it is permitted.

    B. Network statement 10.0.0.0 is not needed on Router B since it is not a directly connected subnet

    C. It will be in the routing table but not advertised out s0

    D. Ping will not work either way. Remember that for ping to work, there must be both transmit and receive. This is very fundamental.

  3. kick me when I’m down
    October 4th, 2016

    Dude, I failed today with a 640. The ‘300-101: Implementing Cisco IP Routing’ exam is completely different then what is on this site. Not even close. There are maybe 10 questions that are the same… What happened???

  4. CCNP student
    February 28th, 2017

    Hello everyone, someone knows why the sim in the exam 300-101, do not accept the command ( copy running-config startup-config), is this command necessary. ? only accept this command in the SIM OSPF stub. when I put the command, showed me this ” Command is not implemented”

  5. Guacca
    August 11th, 2017

    Are we certain Q3 is correct?

    Per Cisco the passive-interface command – “With most routing protocols, the passive-interface command restricts outgoing advertisements only”

    It does not stop incoming routing updates, only outgoing.

    https://www.cisco.com/c/en/us/support/docs/ip/enhanced-interior-gateway-routing-protocol-eigrp/13675-16.html

  6. Guacca
    August 11th, 2017

    Q3 – please update answer to C

    per cisco – “Using the passive interface command can prevent routers from sending routing updates through a router interface.”

    https://www.cisco.com/c/en/us/support/docs/ip/interior-gateway-routing-protocol-igrp/9105-34.html

  7. anu
    August 18th, 2017

    @ Guacca
    yeah Q3 should be option c

  8. Anonymous
    August 21st, 2017
  9. Correction
    September 23rd, 2017

    Question 3

    Which command prevents routers from sending routing updates through a router interface?
    A. default-metric 0
    B. distribute-list in
    C. passive-interface
    D. distribute-list out

    C is the correct answer.

  10. learner
    October 15th, 2017

    I believe

    Question 3 – correct answer should be C. passive-interface
    Which command prevents routers from sending routing updates through a router interface?

    A. default-metric 0
    B. distribute-list in
    C. passive-interface
    D. distribute-list out

    Question is saying “Which command PREVENTS…”

    “Preventing Routing Updates Through an Interface”

    Using the passive interface command can prevent routers from sending routing updates through a router interface. Keeping routing update messages from being sent through a router interface prevents other systems on that network from learning about routes dynamically. For examples using the passive interface command, see the “Passive Interface Examples” section in Configuring IP Routing Protocol-Independent Features.

    For RIP and IGRP, the passive interface command stops the router from sending updates to a particular neighbor, but the router continues to listen and use routing updates from that neighbor; however, on EIGRP, the passive interface command affects the protocol differently, as explained in How Does the Passive Interface Feature Work in EIGRP?

    “Controlling the Processing and Advertising of Routes in Routing Updates”

    To control the advertising and processing of routes in routing updates, use the distribute-list command. There are two distribute-list commands: distribute-list in and distribute-list out. They are similar in syntax, but the options available to each and their behavior are very different.

    The distribute-list in command is used to control which routes are processed in incoming routing updates. See the Using distribute-list in section for an example of this command.

    The distribute-list out command is used to control which routes are included in outgoing routing updates. See the Using distribute-list out section for an example.

    https://www.cisco.com/c/en/us/support/docs/ip/interior-gateway-routing-protocol-igrp/9105-34.html

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