I see, I thought maybe it if was dynagen, that could be the issue. My home lab has 3640s and I did not run into the issue. Strange indeed...
On Fri, Jul 10, 2009 at 8:28 AM, jmangawang <[email protected]> wrote: > This was on a ProctorLabs pod, 109, to be specific. I was working > IPExpert Vol3, Lab9 at the time. The actual scenario occurs between > R1 and BB1 with RIP as the IGP. I know that R9 is running 12.4(3), > but I didn't check R7, R1, or the BB1 routers. I did reboot, several > times, and they all come up the same way. And, I've rebooted both > sides, even though the side with ebgp-multihop sees everything fine. > > I'll try it again on Dynagen this AM and see if there's any difference. > > On Thu, Jul 9, 2009 at 9:01 PM, Bryan Bartik<[email protected]> wrote: > > Hmmmm. Is this real lab or dynagen? Have you rebooted? What version of > code? > > I just set up two routers back to back and I do not get this behavior. > For > > kicks, can you disable all other connections (only leave the connected > > interfaces enabled) and we can try and narrow it down? > > > > On Thu, Jul 9, 2009 at 7:37 PM, jmangawang <[email protected]> wrote: > >> > >> Yeah, it started flapping not long after I posted the first message. > >> So, I stopped advertising the loop0 interface, and created a totally > >> new Loop2 interface assigning them IPs of 7.7.7.7/32 and 9.9.9.9/32 > >> for each respective router. > >> > >> Unfortunately, I'm still getting the same issue, and there's no > >> flapping this time around. Here's R9's config: > >> > >> R9(config-router)#do sh ip bgp > >> BGP table version is 4, local router ID is 50.51.0.9 > >> Status codes: s suppressed, d damped, h history, * valid, > best, i - > >> internal, > >> r RIB-failure, S Stale > >> Origin codes: i - IGP, e - EGP, ? - incomplete > >> > >> Network Next Hop Metric LocPrf Weight Path > >> * 7.7.7.7/32 50.51.0.7 0 0 9 i > >> *> 9.9.9.9/32 0.0.0.0 0 32768 i > >> > >> R9(config-router)#do sh run | s bgp > >> router bgp 7 > >> no synchronization > >> bgp log-neighbor-changes > >> network 9.9.9.9 mask 255.255.255.255 > >> neighbor 50.51.0.7 remote-as 9 > >> neighbor 50.51.0.7 ttl-security hops 2 > >> neighbor 50.51.0.7 update-source Loopback0 > >> no auto-summary > >> R9(config-router)#do sh ip bgp > >> BGP table version is 4, local router ID is 50.51.0.9 > >> Status codes: s suppressed, d damped, h history, * valid, > best, i - > >> internal, > >> r RIB-failure, S Stale > >> Origin codes: i - IGP, e - EGP, ? - incomplete > >> > >> Network Next Hop Metric LocPrf Weight Path > >> * 7.7.7.7/32 50.51.0.7 0 0 9 i > >> *> 9.9.9.9/32 0.0.0.0 0 32768 i > >> > >> R9(config-router)#do sh ip bgp 7.7.7.7/32 > >> BGP routing table entry for 7.7.7.7/32, version 0 > >> Paths: (1 available, no best path) > >> Not advertised to any peer > >> 9 > >> 50.51.0.7 (inaccessible) from 50.51.0.7 (50.51.0.7) > >> Origin IGP, metric 0, localpref 100, valid, external > >> > >> R7, which is set up with ebgp-multihop, sees both routes with best > paths. > >> > >> I finally was able to get it show up properly if I enabled the > >> 'neighbor 50.51.0.7 disable-connected-check' option. > >> > >> R9(config-router)#do sh ip bgp 7.7.7.7/32 > >> BGP routing table entry for 7.7.7.7/32, version 3 > >> Paths: (1 available, best #1, table Default-IP-Routing-Table) > >> Flag: 0x820 > >> Not advertised to any peer > >> 9 > >> 50.51.0.7 (metric 2) from 50.51.0.7 (50.51.0.7) > >> Origin IGP, metric 0, localpref 100, valid, external, best > >> > >> But I couldn't figure out from the description of this option if it > >> broke the ttl-security check. Thoughts? > >> > >> On Thu, Jul 9, 2009 at 8:12 PM, Bryan Bartik<[email protected]> > wrote: > >> > Try "debug ip routing". Are you getting recursion errors? It looks > like > >> > you > >> > are advertising the loopbacks in BGP which will cause the peers to > learn > >> > the > >> > loopback via the loopback. This will cause recursion and removal of > the > >> > route from the BGP table and route table. Then the OSPF route is > chosen, > >> > BGP > >> > comes up and the whole process starts agaon. > >> > > >> > Don't advertise the loopback in BGP unless required or alter the > >> > administrative distances so OSPF is preferred over BGP. > >> > > > > > > > > > -- > > Bryan Bartik > > CCIE #23707 (R&S), CCNP > > Sr. Support Engineer - IPexpert, Inc. > > URL: http://www.IPexpert.com > > > -- Bryan Bartik CCIE #23707 (R&S), CCNP Sr. Support Engineer - IPexpert, Inc. URL: http://www.IPexpert.com
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