[j-nsp] JNCIP EBGP Case Study...

Hoogen hoogen82 at gmail.com
Thu Oct 29 17:56:29 EDT 2009


Okay.. Earlier task required while accepting routes from peer to tag them
with a community and prepend them with as number 65412 twice... I notice
that when I deactivate that.. It works.. So obviously R3 is considering the
routes received from R1 with prepend of 65412 for all P1 routes to be some
sort of as loop... So I guess there is something wrong about it..

Page 568 of the JNCIP books...

-Hoogen

On Thu, Oct 29, 2009 at 2:05 PM, Hoogen <hoogen82 at gmail.com> wrote:

> R1
>
> lab at R1> show configuration routing-options
> static {
>     route 10.0.200.0/24 {
>         next-hop 10.0.1.102;
>         no-readvertise;
>     }
>     route 192.168.10.0/24 reject;
>     route 192.168.100.0/24 reject;
>     route 10.0.0.0/8 {
>         next-hop 10.0.4.13;
>         qualified-next-hop 10.0.4.6 {
>             preference 10;
>         }
>     }
> }
> martians {
>     192.0.2.0/24 orlonger;
> }
> autonomous-system 65000;
> confederation 65412 members [ 65000 65001 65002 ];
>
> lab at R1>
>
> lab at R1> show configuration protocols bgp
> group 65000 {
>     type internal;
>     local-address 10.0.6.1;
>     export ibgp;
>     neighbor 10.0.3.3;
> }
> group p1 {
>     type external;
>     import peer-filter-in;
>     export p1-export;
>     neighbor 10.0.5.254 {
>         peer-as 1492;
>     }
> }
>
> lab at R1>
>
> lab at R1> show configuration policy-options policy-statement ibgp
> term 1 {
>     from {
>         protocol static;
>         route-filter 192.168.10.0/24 exact;
>     }
>     then accept;
> }
> term 2 {
>     from {
>         protocol static;
>         route-filter 192.168.100.0/24 exact;
>     }
>     then {
>         metric 101;
>         local-preference 101;
>         community add no-export;
>         accept;
>     }
> }
>
> lab at R1>
>
> R3 Configuration
>
> lab at R3> show configuration routing-options
> static {
>     route 10.0.200.0/24 {
>         next-hop 10.0.1.102;
>         no-readvertise;
>     }
>     route 192.168.30.0/24 reject;
> }
> martians {
>     192.0.2.0/24 orlonger;
> }
> aggregate {
>     route 10.0.4.0/22;
> }
> autonomous-system 65000;
> confederation 65412 members [ 65000 65001 65002 ];
>
> lab at R3>
>
> lab at R3> show configuration protocols bgp
> advertise-inactive;
> group 65000 {
>     type internal;
>     local-address 10.0.3.3;
>     export ibgp;
>     neighbor 10.0.6.1;
> }
> group c-bgp {
>     type external;
>     multihop;
>     local-address 10.0.3.3;
>     export ibgp;
>     neighbor 10.0.3.4 {
>         hold-time 180;
>         peer-as 65001;
>     }
>     neighbor 10.0.3.5 {
>         peer-as 65002;
>     }
> }
> group t1-t2 {
>     type external;
>     damping;
>     import [ damp trans-filter-in ];
>     export [ no-192-24s prepend ];
>     remove-private;
>     multipath;
>     neighbor 172.16.0.14 {
>         peer-as 65222;
>     }
>     neighbor 172.16.0.18 {
>         peer-as 65222;
>     }
> }
>
> lab at R3>
>
>
> lab at R3> show configuration policy-options policy-statement ibgp
> term 1 {
>     from {
>         protocol static;
>         route-filter 192.168.30.0/24 exact;
>     }
>     then accept;
> }
> term 2 {
>     from community trans-1-2;
>     then {
>         next-hop self;
>     }
> }
>
> lab at R3>
>
> Thanks for your help guys..
>
> -Hoogen
>
> On Thu, Oct 29, 2009 at 3:36 AM, Sean Clarke <sean at clarke-3.demon.nl>wrote:
>
>>
>> What is in your ibgp export policy from R1 to R3  ? Are you putting
>> something in there to cause an issue ?
>>
>>
>>
>>
>>
>>
>> On 10/29/09 10:43 AM, Hoogen wrote:
>>
>> Hi Felix,
>>
>>  Thank you for the reply..
>>
>>  I am not sure how that 17 hidden routes came into play... But its not
>> there now.. I still see the issue..
>>
>>  I had already checked the hidden routes..and those are not the ones
>> which are hiding
>>
>>   lab at R3# run show route receive-protocol bgp 10.0.6.1 hidden extensive
>>
>>  inet.0: 66 destinations, 85 routes (63 active, 0 holddown, 3 hidden)
>>
>>  __juniper_private1__.inet.0: 2 destinations, 2 routes (2 active, 0
>> holddown, 0 hidden)
>>
>>  iso.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden)
>>
>>  [edit]
>> lab at R3#
>>
>>  lab at R3# run show route receive-protocol bgp 10.0.6.1
>>
>>
>>  inet.0: 66 destinations, 85 routes (63 active, 0 holddown, 3 hidden)
>>   Prefix                  Nexthop              MED     Lclpref    AS path
>> * 192.168.10.0/24         10.0.6.1                     100        I
>> * 192.168.100.0/24        10.0.6.1             101     101        I
>>
>>  __juniper_private1__.inet.0: 2 destinations, 2 routes (2 active, 0
>> holddown, 0 hidden)
>>
>>  iso.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden)
>>
>>  [edit]
>> lab at R3#
>>
>>  lab at R3# run show route protocol bgp hidden extensive
>>
>>  inet.0: 66 destinations, 85 routes (63 active, 0 holddown, 3 hidden)
>> 172.17.0.0/16 (1 entry, 0 announced)
>>          BGP                 /-101
>>                 Next-hop reference count: 2
>>                 Source: 172.16.0.14
>>                 Next hop: 172.16.0.14 via ge-0/0/0.0, selected
>>                 State: <Hidden Ext>
>>                 Local AS: 65000 Peer AS: 65222
>>                 Age: 1:27:54
>>                 Task: BGP_65222.172.16.0.14+3227
>>                 AS path: 65222 I
>>                 Localpref: 100
>>                 Router ID: 130.130.0.1
>>
>>  192.0.2.0/24 (1 entry, 0 announced)
>>          BGP                 /-101
>>                 Next-hop reference count: 5
>>                 Source: 172.16.0.18
>>                 Next hop: 172.16.0.18 via ge-0/0/3.0, selected
>>                 State: <Hidden Martian Ext>
>>                 Local AS: 65000 Peer AS: 65222
>>                 Age: 1:28:19
>>                 Task: BGP_65222.172.16.0.18+179
>>                 AS path: 65222 I
>>                 Communities: 65412:102
>>                 Localpref: 100
>>                 Router ID: 130.130.0.2
>>
>>  220.0.0.0/28 (1 entry, 0 announced)
>>          BGP                 /-101
>>                 Next-hop reference count: 5
>>                 Source: 172.16.0.18
>>                 Next hop: 172.16.0.18 via ge-0/0/3.0, selected
>>                 State: <Hidden Ext>
>>                 Local AS: 65000 Peer AS: 65222
>>                 Age: 1:28:19
>>                 Task: BGP_65222.172.16.0.18+179
>>                 AS path: 65222 I
>>                 Localpref: 100
>>                 Router ID: 130.130.0.2
>>
>>  __juniper_private1__.inet.0: 2 destinations, 2 routes (2 active, 0
>> holddown, 0 hidden)
>>
>>  iso.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden)
>>
>> [edit]
>> lab at R3#
>>
>>
>>  The one I am concerned is with group 65000 and I don't have any import
>> policy to deny anything there..
>>
>>   [edit]
>> lab at R3# show protocols bgp
>> advertise-inactive;
>> group 65000 {
>>     type internal;
>>     local-address 10.0.3.3;
>>     export ibgp;
>>     neighbor 10.0.6.1;
>> }
>> group c-bgp {
>>     type external;
>>     multihop;
>>     local-address 10.0.3.3;
>>     export ibgp;
>>     neighbor 10.0.3.4 {
>>         hold-time 180;
>>         peer-as 65001;
>>     }
>>     neighbor 10.0.3.5 {
>>         peer-as 65002;
>>     }
>> }
>> group t1-t2 {
>>     type external;
>>     damping;
>>     import [ damp trans-filter-in ];
>>     export [ no-192-24s prepend ];
>>     remove-private;
>>     multipath;
>>     neighbor 172.16.0.14 {
>>         peer-as 65222;
>>     }
>>     neighbor 172.16.0.18 {
>>         peer-as 65222;
>>     }
>> }
>>
>>  [edit]
>> lab at R3#
>>
>>  This is really strange.. I compared the solutions, and there seems
>> nothing wrong..
>>
>>  -Hoogen
>>
>>  On Thu, Oct 29, 2009 at 1:59 AM, Felix Schueren <
>> felix.schueren at hosteurope.de> wrote:
>>
>>> Hoogen,
>>>
>>> Hoogen wrote:
>>> >>> Now R3 only receives
>>> >>>
>>> >>> lab at R3# run show route receive-protocol bgp 10.0.6.1
>>> >>>
>>> >>> inet.0: 66 destinations, 106 routes (63 active, 0 holddown, 17
>>> hidden)
>>> >>>   Prefix                  Nexthop              MED     Lclpref    AS
>>> path
>>> >>> * 192.168.10.0/24         10.0.6.1                     100        I
>>> >>> * 192.168.100.0/24        10.0.6.1             101     101        I
>>> >>>
>>>  please do
>>> show route receive-protocol bgp 10.0.6.1 hidden extensive
>>>
>>> also paste
>>> show configuration protocols bgp
>>>
>>> both from R3
>>>
>>> Kind regards,
>>>
>>> Felix
>>>
>>> --
>>> Felix Schüren
>>> Head of Network
>>>
>>> -----------------------------------------------------------------------
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>>
>>
>>
>>
>


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