Can't trace route

mitchel · ‎09-10-2002

I have two 3600 series routers I use for provisioning my DSL customers. I noticed something interesting today and was wondering if any one can explain it. I cannot trace route from either 3600 to a any user's IP, however I can trace from my workstation. The customers circuit works fine, I can ping from the router. Cisco 678 on customers end.

From workstation:

Trace 64.240.108.3 ...

1 207.138.224.1 0ms 0ms 0ms TTL: 0 (c7206.nwnetwork.net ok)

2 207.138.224.8 0ms 0ms 0ms TTL: 0 (c3640.nwnetwork.net ok)

3 64.240.108.3 78ms 63ms 62ms TTL: 63 (No rDNS)

From router customer is connected to:

C3640#trace 64.240.108.3

Type escape sequence to abort.

Tracing the route to 64.240.108.3

1 * * *

2 * * *

3 * * *

From core router:

c7206#trace 64.240.108.3

Type escape sequence to abort.

Tracing the route to 64.240.108.3

1 c3640 (207.138.224.8) 0 msec 4 msec 0 msec

2 * * *

3 * * *

Thank you,

Mitchel

ali_khan · ‎09-10-2002

This is normal behavior ......

from 7206 you can get a reply from 3640 first hop to destination but when u send it to workstation IP 64.240.108.3 their stack is not supporting trace reply.

Hope this make sense !

Regards,

mitchel · ‎09-10-2002

So you are saying the Cisco 678 on the users end will not reply? Why then does it reply when I send a trace from my workstation? I am going through the same path:

Trace 64.240.108.3 ...

1 207.138.224.1 15ms 0ms 0ms TTL: 0 (c7206.nwnetwork.net ok)

2 207.138.224.8 0ms 0ms 0ms TTL: 0 (c3640.nwnetwork.net ok)

3 64.240.108.3 62ms 62ms 63ms TTL: 63 (No rDNS)

Thanks

ali_khan · ‎09-10-2002

the setup i understand is

7206--------3640-------wks

correct

or

7206------3640------678------wks ....

is this is the setup make sure through sh ip int xx commads that the icmp unreachiable is enable on the interface ,

regards,

mitchel · ‎09-10-2002

Setup is

wks-----7206------3640-------678

so from wks to 678 no problem, from 7206 or 3640......ng

VA config:

C3640#sh ip int virtual-access 25

Virtual-Access25 is up, line protocol is down

Interface is unnumbered. Using address of FastEthernet3/0 (207.138.224.8)

Broadcast address is 255.255.255.255

MTU is 1500 bytes

Helper address is not set

Directed broadcast forwarding is disabled

Multicast reserved groups joined: 224.0.0.9 224.0.0.5 224.0.0.6

Outgoing access list is not set

Inbound access list is not set

Proxy ARP is enabled

Security level is default

Split horizon is enabled

ICMP redirects are always sent

ICMP unreachables are always sent

ICMP mask replies are never sent

IP fast switching is enabled

IP fast switching on the same interface is enabled

IP Flow switching is disabled

IP Feature Fast switching turbo vector

IP multicast fast switching is enabled

IP multicast distributed fast switching is disabled

IP route-cache flags are Fast

Router Discovery is disabled

IP output packet accounting is disabled

IP access violation accounting is disabled

TCP/IP header compression is disabled

RTP/IP header compression is disabled

Probe proxy name replies are disabled

Policy routing is disabled

Network address translation is disabled

WCCP Redirect outbound is disabled

WCCP Redirect inbound is disabled

WCCP Redirect exclude is disabled

BGP Policy Mapping is disabled

IP multicast multilayer switching is disabled

Thanks,

steve.barlow · ‎09-10-2002

An obvious point here but just in case by some chance it was missed: you checked for any access-lists correct - As traceroute is different depending on the source: http://www.cisco.com/cgi-bin/ViewFAQ.cgi?f=7058

Hope it helps (doubtful but you never know).

Steve

jrkauffman · ‎09-12-2002

When you tracert, your source address is the interface that is the closest to the destination. A point to keep in mind for routing and for access lists.