Thanks for all the responses. Sounds like this behavior could frustrate a
few trying to qualify for their CCIE. Hmmm... now that is an idea.
Deepak Jain
AiNET
On Thu, 21 Oct 1999, Danny McPherson wrote:
>
> [Since this is the Cisco list :-)] Cisco IOS by default rate-limits "ICMP Port
> Unreachable", as well as Source Quench (no others, I believe), message
> generation to two per second. That's why the "middle probe" usually appears
> to be discarded on the *destination* device.
>
> Note that as suggested by your traceroute output, "ICMP Time Exceeded"
> messages, which the client triggers from intermediate hops, aren't throttled
> (per their generation isn't as "hands-on"), that's why the intermediate hops
> don't exhibit this behavior.
>
> And, as you've observed, other OSs do this as well. You can usually tune the
> kernel to modify their behavior ("sysctl" on Linux (and BSD?), "ndd" on
> solaris, other?). The reasoning for the throttling is obvious, I believe,
> especially on routers.
>
> -danny
>
>
> >
> > This might have to go on a Sun-specific list, but has anyone noticed the
> > following behavior: A traceroute goes fine through even many hops, but
> > on last hop, if its a sun server, the -middle- interval shows up as a
> > star, on otherwise pristine connections.
> >
> > Like:
> >
> > (from UUNET)
> >
> > traceroute to allison.clark.net (207.97.14.170), 30 hops max, 40 byte packets
> > 1 passepartout.web.us.uu.net (208.240.88.1) 249.671 ms 4.546 ms
> > 0.587 ms
> > 2 Serial1-1-1.GW2.DCA1.ALTER.NET (137.39.128.205) 3.342 ms 1.765 ms
> > 2.373 ms
> > 3 105.ATM3-0.XR1.DCA1.ALTER.NET (146.188.161.42) 3.454 ms 1.865 ms
> > 1.483 ms
> > 4 295.ATM1-0.TR1.DCA1.ALTER.NET (146.188.161.142) 1.691 ms 1.604 ms
> > 1.720 ms
> > 5 101.ATM6-0.TR1.EWR1.ALTER.NET (146.188.136.186) 7.428 ms 7.212 ms
> > 7.128 ms
> > 6 197.ATM7-0.XR1.NYC1.ALTER.NET (146.188.178.213) 6.281 ms 6.900 ms
> > 6.834 ms
> > 7 195.ATM11-0-0.BR1.NYC1.ALTER.NET (146.188.177.153) 6.723 ms 7.078
> > ms 6.819 ms
> > 8 uunet.nyc1.verio.net (129.250.9.61) 7.423 ms 7.773 ms 7.620 ms
> > 9 nyc1.phl02.verio.net (129.250.3.125) 9.886 ms 9.035 ms 9.415 ms
> > 10 phl02.phl00.verio.net (129.250.3.153) 8.898 ms 8.947 ms 8.066 ms
> > 11 phl00.iad3.verio.net (129.250.3.105) 8.251 ms 8.219 ms 7.780 ms
> > 12 iad3.dca0.verio.net (129.250.2.62) 7.917 ms 8.052 ms 10.563 ms
> > 13 vma1.dca.verio.net (129.250.30.170) 137.615 ms 10.677 ms 347.567 ms
> > 14 fa0-0-0.mae-east6.vma.verio.net (207.22.81.1) 8.990 ms 20.398 ms
> > 113.581 ms
> > 15 allison.clark.net (207.97.14.170) 11.210 ms * 11.294 ms
> >
> > --
> >
> > Nitrous, different target
> >
> > Tracing the route to sprawl.clark.net (198.17.243.6)
> >
> > 1 iad1-core4-pos1-0.atlas.digex.net (165.117.52.186) 0 msec 0 msec 0 msec
> > 2 dca1-core10-pos4-2.atlas.digex.net (165.117.53.33) 0 msec 4 msec 0 msec
> > 3 verio.dca1.atlas.digex.net (165.117.52.242) 0 msec 4 msec 4 msec
> > 4 iad3.dca0.verio.net (129.250.2.62) [AS 2914] 4 msec 4 msec 4 msec
> > 5 vma1.dca.verio.net (129.250.30.170) [AS 2914] 4 msec 0 msec 56 msec
> > 6 fe2-0-0.mae-east.vma.verio.net (207.22.81.16) [AS 2914] 28 msec 4
> > msec 16 msec
> > 7 168.143.0.27 [AS 2914] 4 msec * 4 msec
> >
> >
> > ---
> >
> > Every sun machine (2.5.1, 2.6, 2.7, latest patches) I have tried over a
> > wan does this, over the lan, they are fine. Non-sun machines don't do this
> > (bsd, etc) that I have seen. I have tried multiple types of traceroutes
> > through different networks and different providers.
> >
> > Any clues or am I just imagining things?
> >
> > Deepak Jain
> > AiNET
> >
>
>
>
This archive was generated by hypermail 2b29 : Sun Aug 04 2002 - 04:12:06 EDT