Yes ventre,
As you said, i captured the details of prefix 150.1.6.0 in R3
Rack1R3#sh ip route 150.1.6.0
Routing entry for 150.1.6.0/24
Known via "bgp 100", distance 200, metric 0, type internal
Redistributing via eigrp 100
Advertised by eigrp 100 metric 1500 1 255 1 1500
Last update from 155.1.146.6 00:39:30 ago
Routing Descriptor Blocks:
* 155.1.146.6, from 155.1.13.1, 00:39:30 ago
Route metric is 0, traffic share count is 1
AS Hops 0
MPLS label: none
Rack1R3#
Rack1R3#sh ip route 155.1.13.1
Routing entry for 155.1.13.0/24
Known via "connected", distance 0, metric 0 (connected, via interface)
Redistributing via eigrp 100, bgp 100
Advertised by bgp 100
Routing Descriptor Blocks:
* directly connected, via Serial1/2
Route metric is 0, traffic share count is 1
Rack1R3#
Rack1R3#sh ip cef 150.1.6.0
150.1.6.0/24
nexthop 155.1.37.7 Ethernet0/0
as you see, as per RIB, it should exit via ser1/2, but in cef, next hop
points to a different one. Is it a mismatch between RIB and FIB ?
--Venkee
On 2 February 2012 22:27, Ventre Alessandro <[email protected]> wrote:
> It depends, to clear the cef table
> At first impact i think it is a tipical loop.
> You receive 150.1.6.0/24 from bgp internal,
> exactly 155.1.146.6, from 155.1.13.1 perhaps 13.1 is a RR
> 146.6 in bgp internal admin 200 is the peering address for the neighbor
> the route is learned from, thus neighbor 146.6 under bgp
> if you want reach this prefix probabily you nedd a recursive lookup
> until a outgoing interface is found, in this case is successfull
> because is installed in bgp and rib table. also ibgp route cannot
> adertised to another ibgp peer
>
> rather have you got a mutual redistribution also in bgp? thus from bgp
> in igp ( match community set tag with community list)
> you should verify hop by hop
>
> You do follow commands
> sh ip ei in
> sh ip prot
> sg bg ipv4 u
> sh ip ro
> to each router
>
>
>
> On Thu, Feb 2, 2012, at 07:53 PM, Venkee wrote:
> > Thanks Marc
> >
> > On R3, i have captured the following,
> >
> > Rack1R3(config-router)#do sh ip route 150.1.6.6
> > Routing entry for 150.1.6.0/24
> > Known via "bgp 100", distance 200, metric 0, type internal
> > Redistributing via eigrp 100
> > Advertised by eigrp 100 metric 1500 1 255 1 1500
> > Last update from 155.1.146.6 00:18:27 ago
> > Routing Descriptor Blocks:
> > * 155.1.146.6, from 155.1.13.1, 00:18:27 ago
> > Route metric is 0, traffic share count is 1
> > AS Hops 0
> > MPLS label: none
> > Rack1R3(config-router)#
> > Rack1R3(config-router)#do sh ip cef
> > Prefix Next Hop Interface
> > 0.0.0.0/0 no route
> > 0.0.0.0/8 drop
> > 0.0.0.0/32 receive
> > 127.0.0.0/8 drop
> > 150.1.0.0/16 155.1.37.7 Ethernet0/0
> > 150.1.3.0/24 attached Loopback0
> > 150.1.3.0/32 receive Loopback0
> > 150.1.3.3/32 receive Loopback0
> > 150.1.3.255/32 receive Loopback0
> > 150.1.6.0/24 155.1.37.7 Ethernet0/0
> >
> > As per RIB, the next hop shows the 155.1.13.1, but in CEF, 155.1.37.7 as
> > next hop, so i think i need to clear the cef table
> >
> > Please correct if i am wrong
> >
> > --Venkee
> >
> > On 2 February 2012 18:19, marc abel <[email protected]> wrote:
> >
> > > You need to look at the route on the router 155.1.37.7. It is pointing
> > > back to R3 for some reason.
> > >
> > > On Thu, Feb 2, 2012 at 12:54 AM, Venkee <[email protected]> wrote:
> > >
> > >> Guys,
> > >>
> > >> While making the setup, i noticed the routing loop, may i know the
> reason
> > >> why ? please help
> > >>
> > >> Rack1R5#trace 150.1.6.6
> > >>
> > >> Type escape sequence to abort.
> > >> Tracing the route to 150.1.6.6
> > >>
> > >> 1 155.1.0.3 16 msec 20 msec 20 msec
> > >> 2 155.1.37.7 20 msec 20 msec 20 msec
> > >> 3 155.1.37.3 20 msec 20 msec 20 msec
> > >> 4 155.1.37.7 20 msec 24 msec 20 msec
> > >> 5 155.1.37.3 20 msec 20 msec 16 msec
> > >> 6 155.1.37.7 20 msec 20 msec 20 msec
> > >> 7 155.1.37.3 20 msec 20 msec 20 msec
> > >> 8 155.1.37.7 20 msec 20 msec 20 msec
> > >> 9 155.1.37.3 20 msec 20 msec 20 msec
> > >> 10 155.1.37.7 20 msec 20 msec 20 msec
> > >> 11 155.1.37.3 16 msec 20 msec 16 msec
> > >> 12 155.1.37.7 20 msec 20 msec 20 msec
> > >> 13 155.1.37.3 20 msec 20 msec 20 msec
> > >> 14 155.1.37.7 20 msec 24 msec 20 msec
> > >> 15 155.1.37.3 16 msec 20 msec 20 msec
> > >> 16 155.1.37.7 20 msec 20 msec 20 msec
> > >> 17 155.1.37.3 20 msec 20 msec 20 msec
> > >> 18 155.1.37.7 20 msec 20 msec 20 msec
> > >> 19 155.1.37.3 20 msec 16 msec 20 msec
> > >> 20 155.1.37.7 20 msec 20 msec 20 msec
> > >>
> > >> Rack1R3(config-router)#do sh ip route 150.1.6.6
> > >> Routing entry for 150.1.6.0/24
> > >> Known via "bgp 100", distance 200, metric 0, type internal
> > >> Redistributing via eigrp 100
> > >> Advertised by eigrp 100 metric 1500 1 255 1 1500
> > >> Last update from 155.1.146.6 00:18:27 ago
> > >> Routing Descriptor Blocks:
> > >> * 155.1.146.6, from 155.1.13.1, 00:18:27 ago
> > >> Route metric is 0, traffic share count is 1
> > >> AS Hops 0
> > >> MPLS label: none
> > >> Rack1R3(config-router)#
> > >> Rack1R3(config-router)#do sh ip cef
> > >> Prefix Next Hop Interface
> > >> 0.0.0.0/0 no route
> > >> 0.0.0.0/8 drop
> > >> 0.0.0.0/32 receive
> > >> 127.0.0.0/8 drop
> > >> 150.1.0.0/16 155.1.37.7 Ethernet0/0
> > >> 150.1.3.0/24 attached Loopback0
> > >> 150.1.3.0/32 receive Loopback0
> > >> 150.1.3.3/32 receive Loopback0
> > >> 150.1.3.255/32 receive Loopback0
> > >> 150.1.6.0/24 155.1.37.7 Ethernet0/0
> > >> 155.1.0.0/16 155.1.37.7 Ethernet0/0
> > >> 155.1.0.0/24 attached Serial1/0.1
> > >> 155.1.0.0/32 receive Serial1/0.1
> > >> 155.1.0.3/32 receive Serial1/0.1
> > >> 155.1.0.255/32 receive Serial1/0.1
> > >> 155.1.5.0/24 155.1.0.5 Serial1/0.1
> > >> 155.1.7.0/24 155.1.37.7 Ethernet0/0
> > >> 155.1.8.0/24 155.1.0.5 Serial1/0.1
> > >> 155.1.9.0/24 155.1.37.7 Ethernet0/0
> > >> 155.1.10.0/24 155.1.0.5 Serial1/0.1
> > >> 155.1.13.0/24 attached Serial1/2
> > >> 155.1.13.0/32 receive Serial1/2
> > >>
> > >> Rack1R3(config-router)#do sh ip cef 150.1.6.0
> > >> 150.1.6.0/24
> > >> nexthop 155.1.37.7 Ethernet0/0
> > >>
> > >> do i need to clear the
> > >>
> > >> Regards,
> > >> Venkee
> > >> _______________________________________________
> > >> For more information regarding industry leading CCIE Lab training,
> please
> > >> visit www.ipexpert.com
> > >>
> > >> Are you a CCNP or CCIE and looking for a job? Check out
> > >> www.PlatinumPlacement.com
> > >>
> > >> http://onlinestudylist.com/mailman/listinfo/ccie_rs
> > >>
> > >
> > >
> > _______________________________________________
> > For more information regarding industry leading CCIE Lab training, please
> > visit www.ipexpert.com
> >
> > Are you a CCNP or CCIE and looking for a job? Check out
> > www.PlatinumPlacement.com
> >
> > http://onlinestudylist.com/mailman/listinfo/ccie_rs
> >
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>
> Ventre Alessandro
>
>
>
_______________________________________________
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