Re: BGP backdoor

You're right... I was trying to answer from memory!

Please do send ALL of the configs.

I see you are running MPLS, are you using MP-BGP in the PE network and then
RIP on everything?

(CE7 - RIP & EBGP) ---- (EBGP | MPLS | RIP - RIP | MPLS | EBGP) --- (EBGP &
RIP - CE8)

Is that correct?

On Sep 3, 2010, at 3:43 PM, George Goglidze wrote:

> 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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> >> _______________________________________________________________________
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> >
> > --
> > Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina
> >
> >
> > Blogs and organic groups at http://www.ccie.net
> >
> > _______________________________________________________________________
> > Subscription information may be found at:
http://www.groupstudy.com/list/CCIELab.html
>
>
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>
> _______________________________________________________________________
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Received on Fri Sep 03 2010 - 16:07:56 ART