Re: MPLS vpnv4 - Hiding IPs in traceroute.

They answered the very same question some time ago:
http://www.groupstudy.com/archives/ccielab/200911/msg00042.html

You'll get you answer there ;)

Nicolas
http://ccie-en-espanol.blogspot.com/

On Mon, Jan 11, 2010 at 5:55 PM, Jack Router <pan.router_at_gmail.com> wrote:

> Hello all.
>
> I have a question regarding ttl propagation in mpls. This is the topology:
>
> Host1 -- R1(CE) -- R2(PE) -- R3(P) -- R4(P) -- R5(PE) -- R6(CE) -- Host2
>
> MPLS runs on PE and P routers (R2, R3, R4, R5)
> OSPF runs on PE and P routers (R2, R3, R4, R5)
> MP-BGP runs on PE routers (R2 and R5)
> RIP runs on PE and CE routers (R1, R2 and R5, R6)
> MPLS ldp, VPNv4, VRFs etc configured and appear to be working correctly as
> I
> have connectivity across the cloud.
>
> Ping from Host1 to Host2 with "mpls ip propagate-ttl forwarded" (default
> setting):
> Host1#trace 172.16.51.12
> 1 172.16.50.1 12 msec 52 msec 64 msec
> 2 10.1.12.2 112 msec 104 msec 48 msec
> 3 10.1.23.3 [MPLS: Labels 300/510 Exp 0] 220 msec 348 msec 296 msec
> 4 10.1.24.4 [MPLS: Labels 405/510 Exp 0] 332 msec 312 msec 244 msec
> 5 10.1.56.5 [MPLS: Label 510 Exp 0] 176 msec 212 msec 232 msec
> 6 10.1.56.6 304 msec 228 msec 288 msec
> 7 172.16.51.12 272 msec * 308 msec
>
> Ping from Host1 to Host2 with "NO mpls ip propagate-ttl forwarded" on ALL
> mpls routers (PE and P):
> Host1#trace 172.16.51.12
> 1 172.16.50.1 28 msec 56 msec 56 msec
> 2 10.1.12.2 56 msec 52 msec 52 msec
> 3 10.1.56.5 [MPLS: Label 510 Exp 0] 172 msec 212 msec 164 msec
> 4 10.1.56.6 320 msec 228 msec 324 msec
> 5 172.16.51.12 300 msec * 364 msec
>
> The question is why I see MPLS Label information from R5 (PE router, egress
> interface 10.1.56.5, line #3) even if mpls ttl is disabled? Is this normal?
> Is it possible to configure the network so only CE routers will be visible
> in the trace ?
>
> Thanks,
>
>
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>
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Received on Mon Jan 11 2010 - 18:08:49 ART