Re: BGP backdoor

Hi Adrian,

That's how you define backdoor route... you define network that you receive
from ebgp neighbour and put backdoor at the end.
So until that everything is fine.
Being the same AS is fine too, as they are NOT considered ibgp because the
neighbor is in different AS.
It just means that the same as is permitted in AS_PATH with command
allowas-in

It should work fine really. Can you give us the whole configuration of CE7/8
??? Including RIP ?
As well, can you shutdown BGP completely and show us show ip route when BGP
is shutdown?

Thanks,

On Fri, Sep 3, 2010 at 7:44 PM, Adrian Brayton <abrayton_at_gmail.com> wrote:

> This is just a shot in the dark but looking at your configuration...
>
> On CE7, why are you advertising this:
>
> network 10.5.8.0 mask 255.255.255.0 backdoor
>
> On CE8, why are you advertising this:
>
> network 10.5.7.0 mask 255.255.255.0 backdoor
>
> What I think you are missing is that you cant add the "backdoor" command to
> a network that someone else is advertising.
>
> The network "10.5.7.0" is on CE7, but you have the backdoor command on CE8.
> The same for the other CE router.
>
> I could be wrong and I am sure that if I am that it will be pointed out
> more than once!
>
> HTHs
>
> On Sep 3, 2010, at 11:45 AM, Carlos G Mendioroz wrote:
>
> > Srinivas,
> > the AD of the route that is there is 20, so the problem seems to be that
> > backdoor is not kicking in.
> >
> > srinivas pv @ 3/9/2010 9:38 -0300 dixit:
> >> Hi,
> >> I think CE routes are not getting propagated through RIP. Could you try
> >> shutting down interfaces between CE and PE, so that you should see
> routes
> >> through RIP.
> >> Thanks,
> >> Srinivas
> >> On Fri, Sep 3, 2010 at 11:09 AM, selamat pagi <ketimun_at_gmail.com>
> wrote:
> >>> Trying to understand the usage of backdoor command in BGP.
> >>>
> >>> This is my Lab-setup. With the neigbors-loopbacks configured as
> backdoor,
> >>> I
> >>> would expect to see CE7 lo on CE8 as a RIP-route.
> >>> But I still get the eBGP route vie PE.
> >>>
> >>> ------------------------------------RIP
> ----------------------------------
> >>> |
> >>> |
> >>> CE7 -- eBGP --- PE2 --- MPLS --- PE5 -- eBGP -- CE8
> >>>
> >>>
> >>> CE7
> >>> interface Loopback0
> >>> ip address 10.5.7.7 255.255.255.0
> >>>
> >>> router bgp 200
> >>> no synchronization
> >>> bgp router-id 10.5.7.7
> >>> bgp log-neighbor-changes
> >>> network 10.5.7.0 mask 255.255.255.0
> >>> network 10.5.8.0 mask 255.255.255.0 backdoor
> >>> neighbor 10.5.27.2 remote-as 100
> >>> neighbor 10.5.27.2 allowas-in
> >>>
> >>>
> >>> CE8
> >>> interface Loopback0
> >>> ip address 10.5.8.8 255.255.255.0
> >>>
> >>> router bgp 200
> >>> bgp router-id 10.5.8.8
> >>> network 10.5.7.0 mask 255.255.255.0 backdoor
> >>> network 10.5.8.0 mask 255.255.255.0
> >>> neighbor 10.5.58.5 remote-as 100
> >>> neighbor 10.5.58.5 allowas-in
> >>>
> >>>
> >>> R8#sh ip route
> >>> 158.5.0.0/32 is subnetted, 1 subnets
> >>> B 158.5.6.6 [20/0] via 10.5.58.5, 14:53:51
> >>> 10.0.0.0/24 is subnetted, 5 subnets
> >>> C 10.5.8.0 is directly connected, Loopback0
> >>> B 10.5.7.0 [20/0] via 10.5.58.5, 00:00:06 <-- would expect
> to
> >>> get this via RIP
> >>> R 10.5.27.0 [120/1] via 10.5.78.7, 00:00:18, Vlan78
> >>> C 10.5.58.0 is directly connected, Vlan58
> >>> C 10.5.78.0 is directly connected, Vlan78
> >>>
> >>>
> >>> What do I miss here ?
> >>>
> >>> Thanks, keti
> >>>
> >>>
> >>>
> >>>
> >>>
> http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a00800c95bb.shtml#bgpbackdoor
> >>>
> >>>
> >>> Blogs and organic groups at http://www.ccie.net
> >>>
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> >
> > --
> > Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina
> >
> >
> > Blogs and organic groups at http://www.ccie.net
> >
> > _______________________________________________________________________
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>
>
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>
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Received on Fri Sep 03 2010 - 20:43:09 ART