RIPv2 Filtering with Standard Access-Lists

 

Just a variation on the solution: we filter even 3rd octet and of course permit all other updates coming in, instrad of permitting odd 3rd octet and inplicitly denying all other updates.

 

use this access list to filter routes with an even number in the third octet

R6(config)#access-list 1 deny 0.0.0.0 255.255.254.255

R6(config)#access-list 1 permit any

R6(config)#end


R6(config)#router rip

R6(config-router)# distribute-list 1 in

R6(config-router)#end

R6# clear ip route *



we would get the same result 


R6#sh ip route rip | b Ga

Gateway of last resort is not set


      150.1.0.0/32 is subnetted, 6 subnets

R        150.1.1.1 [120/1] via 155.1.146.1, 00:00:26, Ethernet0/0.146

R        150.1.3.3 [120/2] via 155.1.146.1, 00:00:26, Ethernet0/0.146

                   [120/2] via 155.1.67.7, 00:00:10, Ethernet0/0.67

R        150.1.5.5 [120/2] via 155.1.146.1, 00:00:26, Ethernet0/0.146

R        150.1.7.7 [120/1] via 155.1.67.7, 00:00:10, Ethernet0/0.67

R        150.1.9.9 [120/2] via 155.1.67.7, 00:00:10, Ethernet0/0.67

      155.1.0.0/16 is variably subnetted, 11 subnets, 2 masks

R        155.1.5.0/24 [120/2] via 155.1.146.1, 00:00:26, Ethernet0/0.146

R        155.1.7.0/24 [120/1] via 155.1.67.7, 00:00:10, Ethernet0/0.67

R        155.1.9.0/24 [120/2] via 155.1.67.7, 00:00:10, Ethernet0/0.67

R        155.1.13.0/24 [120/1] via 155.1.146.1, 00:00:26, Ethernet0/0.146

R        155.1.37.0/24 [120/1] via 155.1.67.7, 00:00:10, Ethernet0/0.67

R        155.1.45.0/24 [120/2] via 155.1.146.1, 00:00:26, Ethernet0/0.146

R        155.1.79.0/24 [120/1] via 155.1.67.7, 00:00:10, Ethernet0/0.67

R6#


Comments

  • the task asked for one-line standard access-list on R6, the variation does not accomplish exactly the task as stated, but gives a solution if the task did not require exactly one-line standard access-list, and alloed the use of multiple-line atandard access-list.

    ============================================================================

    Just a variation on the solution: we filter even 3rd octet and of course permit all other updates coming in, instrad of permitting odd 3rd octet and inplicitly denying all other updates.

     

    use this access list to filter routes with an even number in the third octet

    R6(config)#access-list 1 deny 0.0.0.0 255.255.254.255

    R6(config)#access-list 1 permit any

    R6(config)#end


    R6(config)#router rip

    R6(config-router)# distribute-list 1 in

    R6(config-router)#end

    R6# clear ip route *



    we would get the same result 


    R6#sh ip route rip | b Ga

    Gateway of last resort is not set


          150.1.0.0/32 is subnetted, 6 subnets

    R        150.1.1.1 [120/1] via 155.1.146.1, 00:00:26, Ethernet0/0.146

    R        150.1.3.3 [120/2] via 155.1.146.1, 00:00:26, Ethernet0/0.146

                       [120/2] via 155.1.67.7, 00:00:10, Ethernet0/0.67

    R        150.1.5.5 [120/2] via 155.1.146.1, 00:00:26, Ethernet0/0.146

    R        150.1.7.7 [120/1] via 155.1.67.7, 00:00:10, Ethernet0/0.67

    R        150.1.9.9 [120/2] via 155.1.67.7, 00:00:10, Ethernet0/0.67

          155.1.0.0/16 is variably subnetted, 11 subnets, 2 masks

    R        155.1.5.0/24 [120/2] via 155.1.146.1, 00:00:26, Ethernet0/0.146

    R        155.1.7.0/24 [120/1] via 155.1.67.7, 00:00:10, Ethernet0/0.67

    R        155.1.9.0/24 [120/2] via 155.1.67.7, 00:00:10, Ethernet0/0.67

    R        155.1.13.0/24 [120/1] via 155.1.146.1, 00:00:26, Ethernet0/0.146

    R        155.1.37.0/24 [120/1] via 155.1.67.7, 00:00:10, Ethernet0/0.67

    R        155.1.45.0/24 [120/2] via 155.1.146.1, 00:00:26, Ethernet0/0.146

    R        155.1.79.0/24 [120/1] via 155.1.67.7, 00:00:10, Ethernet0/0.67

    R6#



     

  • JoeMJoeM ✭✭✭

    access-list 1 deny 0.0.0.0 255.255.254.255
    access-list 1 permit any

    Yes, this would work for part of the solution. But be careful when reading the lab requirements. 

    In this case, "...a one-line standard access-list..." would mean that your solution gets zero points.

     

  • Thanks JoeM,

    Indeed, I did not read the task word by word !!!!!!!!!!

    and the two-line standard access-list gives me 0 points for my answer.

    =======================================================

     

     

    access-list 1 deny 0.0.0.0 255.255.254.255
    access-list 1 permit any

    Yes, this would work for part of the solution. But be careful when reading the lab requirements. 

    In this case, "...a one-line standard access-list..." would mean that your solution gets zero points.

     

     

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