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#1 - 03/01/99 03:49 PM Routing Problem (missing hop data)
Pete Ness Offline



Registered: 08/30/99
Posts: 1106
Loc: Boise, Idaho
Here's an instance of a problem that a few people have had. I've included an copy of the original message and my response.<br><br>It *looks* like this is a problem with the router, but maybe someone else has some experience with this? Please comment!<br><br>Original Message<br><br>Hi,<br>I was using a 3com SmartIQ ISDN modem then switched to a Dlink DI-106W ISDN router. Previous to this switch, PP worked great. Now, I get a chart but there are a number of nodes with no names and no stats and just a straight line that runs from the first to the last node. Attached is an example:<br><br><br><br>Do you have a clue as to why it comes out like this and what can be done about it????<br><br><br>My (Pete) Response<br><br>Let's say that the router at hop 1 is the problem.<br> <br>1) A packet is sent out with a TTL of 1. It reaches hop 1 and the TTL is decremented to 0. Hop 1 returns that packet as undeliverable with it's wn IP address - which Ping Plotter records (and does a DNS lookup on - although the DNS lookup is irrelevant to our problem).<br><br>2) Another packet is sent out - with a TTL of 2. Hop 1 decrements it one - and sends it on. Hop 2 decrements it another one down to 0 and returns it back to you because the TTL has expired. The router at hop 1 decides it doesn't actually want to return the expired echo requests, so it just discards it.<br><br>3) A third packet is sent out, with a TTL of 3 this time. It's returned and "dropped" at hop 1 again.<br><br>4) The packet is sent with a TTL of 4 - same results as hop 3.<br><br>5) The packet is sent with a TTL of 5. The router at hop 5 receives this packet - and since it's destined for it's IP address, it returns a valid ICMP echo response (this time, it's not expired). This travels back again, but because this isn't a response to an expired request, hop 1 allows the packet back to you.<br><br>I'm not exactly sure this is what's happening - but this scenario describes the behavior we're seeing, so this is my running theory right now. I'm hoping that someone will be able to confirm this pretty soon.<br><br><br>

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#2 - 04/20/99 06:55 AM Re: Routing Problem (missing hop data) [Re: Pete Ness]
phd Offline


Registered: 08/30/99
Posts: 3
Pete,<br><br>I am encountering precisely the same kind of anomaly you are describing;<br>however, as a control, a competing product, neotrace, gives a perfectly good trace<br>for the same route, so I cannot really blame any router on the path.<br>If you need it, I could post some sample anomalous traces.<br><br>Regards,<br><br>__philippe<br><br>

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#3 - 04/20/99 08:13 PM Re: Routing Problem (missing hop data) [Re: phd]
Pete Ness Offline



Registered: 08/30/99
Posts: 1106
Loc: Boise, Idaho
Hi Philippe.<br><br>Thanks for the info.<br><br>What kind of results do you get when you use the Command-line based tool "TRACERT"? I'm trying to identify if this is a problem with Ping Plotter specifically - or if it's something with the Microsoft ICMP.DLL that's causing the problems.<br><br>Thanks!<br><br>Pete<br><br><br>

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#4 - 04/21/99 04:04 AM Re: Routing Problem (missing hop data) [Re: Pete Ness]
phd Offline


Registered: 08/30/99
Posts: 3
Hello Pete,<br><br>Tracert produces what seems to me a perfectly good trace results for the same query where<br>Ping Plotter starts missing hop data after the first few hops.<br><br>I will e-mail you a sample trace for both Ping Plotter and Tracert.<br><br>One more thing I remember: Ping Plotter used to work perfectly well here until<br>we changed our Internet Service Provider; after that, PP started to misbehave.<br><br>Regards.<br><br>__philippe<br><br>

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#5 - 05/28/99 06:28 PM Re: Routing Problem (missing hop data) [Re: phd]
jamespole Offline


Registered: 08/30/99
Posts: 1
this is a example of a windows tracert command:-<br> 1 138 ms 145 ms 144 ms max41.akl.ihug.co.nz [203.29.165.41]<br> 2 138 ms 146 ms 146 ms feth-0-1-tig-nz-akl-1.ihug.net [203.29.165.254]<br> 3 522 ms 491 ms 519 ms atm5-0-0-1-tig-nz-akl-1.ihug.net [202.49.88.42]<br> 4 644 ms 651 ms 626 ms 202.37.246.249<br> 5 489 ms 497 ms 484 ms Serial1-1-0.GW1.LAX4.ALTER.NET [157.130.224.89]<br> 6 467 ms 495 ms 470 ms 121.ATM3-0.XR2.LAX4.ALTER.NET [146.188.248.110]<br> 7 480 ms 470 ms 479 ms 192.ATM3-0.TR2.LAX2.ALTER.NET [146.188.249.6]<br> 8 547 ms 565 ms 533 ms 111.ATM7-0.TR2.CHI4.ALTER.NET [146.188.136.141]<br> 9 561 ms 561 ms 541 ms 298.ATM6-0.XR2.CHI6.ALTER.NET [146.188.209.9]<br> 10 563 ms 570 ms 549 ms 190.ATM8-0-0.GW2.CHI6.ALTER.NET [146.188.208.181]<br> 11 544 ms 545 ms 551 ms UU-ds3.axxs.net [157.130.101.114]<br> 12 525 ms 550 ms 529 ms CI-DS3-DFW.PROPAGATION.NET [216.71.87.10]<br> 13 549 ms 545 ms 528 ms nessoft.com [216.71.46.33]<br><br>And a pingplotter one:-<br><br><br>

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#6 - 06/04/99 03:59 AM Re: Routing Problem (missing hop data) [Re: phd]
phd Offline


Registered: 08/30/99
Posts: 3
ahem...<br><br>Any news on the "missing hop data" front...?<br><br>__philippe<br><br>

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#7 - 06/07/99 08:47 PM Re: Routing Problem (missing hop data) [Re: phd]
Pete Ness Offline



Registered: 08/30/99
Posts: 1106
Loc: Boise, Idaho
Well ...<br><br>Progress is going well on a new underlying core that I *hope* should address this problem (along with many others). I hope to have a beta available sometime pretty soon - although I don't know exactly when "soon" is.<br><br>So, that's two hopings and a couple of soons - nothing particularily firm. I'll e-mail you when I get something ready that you can have a look at.<br><br>Thanks for checking up on me <g>.<br><br>Pete<br><br><br>

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