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Larry Pieniazek <lar@voyager.net> wrote:
> if someone tells me what to look for specifically (pretend you're
> talking to a manager :-) ) I'll post ones that help determine what the
> problem is, and drop the rest on the floor
If I were talking to a manager, I'd say: don't worry, we'll take care of it.
*grin*
But:
IP packets have a property called Time-To-Live. It's a counter, and each
time a packet goes through a gateway, it's decremented. (By default, most
packets are set to thirty, so that's in general the farthest away anything
can be and still be reachable.) Anyway, once this counter reaches zero, that
gateway drops the packet and sends back a Time Exceeded Message.
Traceroute works by sending packets towards your destination and counting
the time it takes to get a TEM back from each one. The first packet sent out
gets a TTL of one, then two, and so on. So, the first packet tells you
(roughly) the time to and from the first router, the second the time for the
second router, and so on. Of course, it stops when the packet actually
reaches its destination.
Actually, most traceroute programs send out three packets for each value. So
what you end up with is something like this:
1 128.197.185.1 1.007 ms 0.869 ms 1.508 ms
2 128.197.254.5 2.165 ms 1.810 ms 2.643 ms
3 157.130.7.69 4.655 ms 3.309 ms 3.368 ms
4 146.188.176.234 2.315 ms 2.524 ms 2.868 ms
5 146.188.176.174 12.597 ms 17.690 ms 18.368 ms
6 146.188.177.153 21.423 ms 15.423 ms 16.150 ms
7 206.132.150.129 15.455 ms 11.166 ms 11.553 ms
8 206.132.253.97 16.484 ms 9.011 ms 9.696 ms
9 206.132.151.22 148.602 ms 148.816 ms 161.058 ms
10 206.132.254.41 147.507 ms 144.997 ms 142.788 ms
11 208.178.103.62 147.656 ms 148.809 ms 160.184 ms
12 204.71.200.74 156.666 ms 175.413 ms 179.378 ms
The first column is the TTL value (and therefore how "far away" that gateway
is), the second is the IP of the gateway which sent the timeout message, and
the last three represent the times. If you see a "*" there, the packet never
came back. (Often this is because of paranoid router settings -- check out
www.microsoft.com, for example.) Things like "!H" are also bad signs -- that
means "Host unreachable".
Of course, the time to go through five gateways necessarily includes the
time to go through the four on the way to that. So if you see really high
numbers early on, any lower numbers after that are suspect. Traceroute is
great for finding out where the first problems are, but can't help you much
beyond that.
--
Matthew Miller ---> mattdm@mattdm.org
Quotes 'R' Us ---> http://quotes-r-us.org/
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Message has 2 Replies:
 | | Re: Sluggish nntp performance
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| (...) Oh, I've been a manager... but I stopped. Didn't like it and neither did any of the people I was managing. *no idea* why, really. LOL... <snipped excellent explanation> (...) Lemme see if I got it then, in this example the problem lies either (...) (25 years ago, 13-Oct-99, to lugnet.admin.general, lugnet.off-topic.geek)
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Message is in Reply To:
| | Re: Sluggish nntp performance
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| I can TRY more tracerts... I get around so get a chance to try from a lot of different places. if someone tells me what to look for specifically (pretend you're talking to a manager :-) ) I'll post ones that help determine what the problem is, and (...) (25 years ago, 12-Oct-99, to lugnet.admin.general)
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