At 02:36 PM 9/14/01, Wilson, Bradley wrote:
>So would the "missing hop" syndrome be caused by a router or firewall which
>is filtering any and all UDP packets (which a good portion of them are)?
UDP or Ping are not relevant until you get to the final destination. The IP
datagrams don't make it past the IP layer at the intermediate hops because
the IP router decrements the TTL, drops the packet, and sends ICMP TTL
exceeded.
The missing hops could be because ICMP TTL exceeded is rate limited or
filtered. Some service providers purposely don't send these to hide some of
their internal hops.
Gotta run.
Priscilla
>-----Original Message-----
>From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]]
>Sent: Friday, September 14, 2001 1:57 PM
>To: [EMAIL PROTECTED]
>Subject: RE: traceroute [7:19963]
>
>
>At 01:14 PM 9/14/01, Wilson, Bradley wrote:
> >What you're seeing isn't a problem related to timeouts. Essentially, all
a
> >"trace" is is a series of regular ICMP pings with incremening TTL fields.
>
>Agreed, but just wanted to add that Cisco and Unix send a UDP packet when
>doing traceroute, not a ping. Microsoft sends an ICMP ping.
>
> >If a particular router (say, the last hop when your TTL is set to 4) is
> >configured to not respond to pings, you'll get a timeout.
>
>Only the last device would respond to the ping anyway. But the router could
>be rate limiting TTL exceeded messages or configured not to send them.
>
>Priscilla
>
> >However, the
> >routers on either side of it (the ones you hit when your TTL is set to 3
or
> >5, respectively) may respond to pings normally. Really nothing you can do
> >about the one that timed out if it's not under your administrative
control.
> >
> >BJ
> >
> >
> >
> >-----Original Message-----
> >From: khramov [mailto:[EMAIL PROTECTED]]
> >Sent: Friday, September 14, 2001 12:06 PM
> >To: [EMAIL PROTECTED]
> >Subject: traceroute [7:19963]
> >
> >
> >sometimes when I do a traceroute it skeeps some routers. Is there any
> >way to adjusst time out or something to get traceroute to show all the
> >routers that packet is going through?
> >
> >Regards,
> >Alex
> >
> >[GroupStudy.com removed an attachment of type text/x-vcard which had a
name
> >of khramov.vcf]
>________________________
>
>Priscilla Oppenheimer
>http://www.priscilla.com
________________________
Priscilla Oppenheimer
http://www.priscilla.com
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=19995&t=19963
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