From: MADMAN (dave@interprise.com)
Date: Wed Sep 11 2002 - 18:46:23 GMT-3
Yes I was agreeing with you only pointing out that Cisco isn't unique
in their implementation. I didn't realize Microsoft used ICMP though!!
Dave
Brian Dennis wrote:
>
> The confusion seems to be in how some vendors trigger a device to send
> back the ICMP time exceeded message. Cisco sends UDP packets and
> Microsoft sends ICMP echos as stated earlier. It's not a great idea to
> generate an ICMP message about another ICMP message and is why some
> vendors chose to use UDP.
>
> Generating an ICMP message about another ICMP message is kind of like
> opening a trouble ticket about another trouble ticket ;-) But the
> reasoning behind it was that some devices might actually be listening to
> the same UDP port of the packet that the traceroute application is
> sending to. This would cause the final ICMP port unreachable to not be
> generated. Since basically all devices will reply to an echo, some
> vendors implemented traceroute using ICMP echos to trigger the
> responses.
>
> btw... I'm not sure if you're agreeing with me or trying to point
> something else out ;-)
>
> Brian Dennis, CCIE #2210 (R&S/ISP Dial)
>
> -----Original Message-----
> From: MADMAN [mailto:dave@interprise.com]
> Sent: Wednesday, September 11, 2002 1:16 PM
> To: Brian Dennis
> Cc: 'Becky Qiang'; ccielab@groupstudy.com
> Subject: Re: non-ICMP ping and non-ICMP traceroute
>
> I think that's typical. Increment the TTL by one utilizing the time
> exceeded ICMP message is what traceroute does as it is itself not an
> ICMP packet.
>
> Dave
>
> Brian Dennis wrote:
> >
> > Cisco's implementation of traceroute (IOS and CatOS) is not based on
> > sending ICMP packets. It's based on sending UDP packets.
> >
> > Brian Dennis, CCIE #2210 (R&S/ISP Dial)
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of
> > Becky Qiang
> > Sent: Wednesday, September 11, 2002 11:05 AM
> > To: Ravi Chandran; ccielab@groupstudy.com
> > Subject: Re: non-ICMP ping and non-ICMP traceroute
> >
> > I've heard of such thing. Both ping and traceroute command in Cisco
> CLI
> > are
> > developed based on ICMP...Becky
> >
> > ----- Original Message -----
> > From: "Ravi Chandran" <s_ravichandran@hotmail.com>
> > To: <ccielab@groupstudy.com>
> > Sent: Wednesday, September 11, 2002 9:09 AM
> > Subject: non-ICMP ping and non-ICMP traceroute
> >
> > > Hi everyone,
> > >
> > > While in a telenet session on a Cisco switch, can I generate a
> > non-ICMP
> > > ping and non-ICMP traceroute from the command line?
> > >
> > >
> > >
> > > Thanks.
> > >
> > > Ravi
> > >
> > >
> >
> ------------------------------------------------------------------------
> > >
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> --
> David Madland
> CCIE# 2016
> Sr. Network Engineer
> Qwest Communications
> 612-664-3367
>
> "You don't make the poor richer by making the rich poorer." --Winston
> Churchill
-- David Madland CCIE# 2016 Sr. Network Engineer Qwest Communications 612-664-3367"You don't make the poor richer by making the rich poorer." --Winston Churchill
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