05-07-2019 04:14 PM
Hello,
I have this bgo config
!
bgp multiple-instance
!
router bgp 65501
max-paths ebgp 2
redistribute kernel
neighbor 192.168.88.1 remote-as 64520
neighbor 192.168.88.1 ebgp-multihop 255
neighbor 192.168.88.1 soft-reconfiguration inbound
neighbor 192.168.88.1 prefix-list epg-in in
neighbor 192.168.88.1 prefix-list epg-out out
neighbor 192.168.88.1 as-override
neighbor 192.168.99.1 remote-as 64520
neighbor 192.168.99.1 ebgp-multihop 255
neighbor 192.168.99.1 soft-reconfiguration inbound
neighbor 192.168.99.1 prefix-list web-in in
neighbor 192.168.99.1 prefix-list web-out out
neighbor 192.168.99.1 as-override
!
In ingress direction I correctly filter only the routes I need
VPX-LB-01#sh ip bgp neighbors 192.168.88.1 routes
Node Id: 0
BGP table version is 9, local router ID is 192.168.99.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, l - labeled
S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* 10.10.0.0/24 0.0.0.0 0 0 64520 65504 ?
Total number of prefixes 1
VPX-LB-01#sh ip bgp neighbors 192.168.99.1 routes
Node Id: 0
BGP table version is 9, local router ID is 192.168.99.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, l - labeled
S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* 0.0.0.0/0 0.0.0.0 0 0 64520 65505 i
Total number of prefixes 1
I see the routes in the bgp db:
VPX-LB-01#sh ip bgp
Node Id: 0
BGP table version is 10, local router ID is 192.168.99.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, l - labeled
S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* 0.0.0.0/0 0.0.0.0 0 0 64520 65505 i
* 10.10.0.0/24 0.0.0.0 0 0 64520 65504 ?
I read online that next-hop 0.0.0.0 means "locally generated route" but that is not the case :) i would expect the neighbor, being ebgp, to be neighbor address (192.168.88.1 or 99.1)
the routes are not in the routing table
VPX-LB-01#sh ip route bgp
Node Id: 0
Gateway of last resort is not set
VPX-LB-01#
export policies are matching the right routes
VPX-LB-01#sh ip bgp prefix-list epg-out
Node Id: 0
BGP table version is 11, local router ID is 192.168.99.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, l - labeled
S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* 0.0.0.0/0 0.0.0.0 0 0 64520 65505 i
Total number of prefixes 1
VPX-LB-01#sh ip bgp prefix-list web-out
Node Id: 0
BGP table version is 11, local router ID is 192.168.99.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, l - labeled
S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* 10.10.0.0/24 0.0.0.0 0 0 64520 65504 ?
but nothing is announced:
VPX-LB-01#sh ip bgp neighbors | include announced
0 announced prefixes
0 announced prefixes
can anyone help me understand what I am missing?
thanks in advance for the help
Umberto
05-07-2019 08:27 PM
The fact that the routes are not installed in the RIB is likely due to the fact that the next hop 0.0.0.0 is considered unreachable. The next hop is sent as part of the BGP update. You seem to be running Quagga. Are neighbors 192.168.88.1 and 192.168.99.1 Quagga as well? Is it possible that they set the next hop to 0.0.0.0?
Could you please provide a "show ip bgp 10.0.0.0/24"?
Regards,
05-08-2019 12:44 AM
VM is a citrix netscaler
BGP neighbor is Juniper Contrail
here is my output
VPX-LB-01#sh ip bgp 10.10.0.0/24
Node Id: 0
BGP routing table entry for 10.10.0.0/24
Paths: (1 available, no best path)
Not advertised to any peer
64520 65504
0.0.0.0 (inaccessible) from 192.168.88.1 (192.168.200.10)
Origin incomplete metric 0, localpref 100, valid, external
Last update: Wed May 8 09:34:57 2019
2 issues
- no best path
- inaccessible nh (0.0.0.0)
so according to this it is correct not to see the bgp route
I captured packets on the citrix VM port inorder to lacate BGP update messages
As you can see the next-hop is set correctly to 192.168.88.1 so it seems that somehow the VM ignored that value
05-08-2019 01:14 AM
Hello,
on a side note, I tried to recreate this in GNS3 with only Cisco routers, it seems to work as designed. I understand that you are using virtual routers, so maybe that is the problem...
05-08-2019 01:53 AM
what kind of problem do you think might be related to using VMs?
the BGP update has the correct next-hop
but inside next-hop scaler that is overridden by 0.0.0.0
ping to 192.168.88.1 is working fine
05-08-2019 07:14 AM - edited 05-08-2019 07:15 AM
> 2 issues
> - no best path
> - inaccessible nh (0.0.0.0)
In fact, it is only one issue. The "no best path" condition is actually due to the next hop being unreachable.
The Citrix NetScaler seems to be resetting the next hop for some reason. You should probably check with your Citrix support team why that might be.
I am not sure it is related, but is there any reason you configured "neighbor 192.168.88.1 ebgp-multihop 255"? It it not needed if the neighbor is directly connected.
Regards,
05-08-2019 07:40 AM
yeah,
i agree we need support from citrix
by the way, ebgp multihop is needed in order to establish session with contrail vrouter
05-08-2019 09:23 AM
I just noticed that you have next hop address within the MP_REACH_NLRI. Could you please expand this field so that we can see what it contains?
Regards,
05-07-2019 08:29 PM
Only best routes are advertised to neighbor's over Bgp.
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