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Re: Access to the Internic Blocked -- LSRR, traceroute with ICMP

  • From: Ehud Gavron
  • Date: Thu Aug 22 03:08:17 1996

>	Speaking of which, is anyone going to implement traceroute
>for UNIX which using icmp echo requests, instead of (semi-)random
>udp packets, as the ammo?  This is one way which I think Microsoft out
>did the old UNIX implementations.

   They're not semi (or quasi) random udp packets.  They're sequential

   Secondly, current router vendors' decisions to prioritize ICMP echo
   request as dung-level packets means that traceroute's UDP packets 
   actually get through at times when pings don't.

   Third, I'd be happy to implement it... but I'm not sure this would 
   be a win.  I can see the loss (see paragraph 2), but WHAT is the
   big win???

   p.s. The original question was based on Vadim's rhetorical query
        as to router vendors.  Learn to differentiate between WISHFUL
        THINKING and routing reality.  When router vendors pledge to
        not drop, and properly route lsrr icmp echo request/reply 
        that code will be online within 24 hours.

>	The combination of the above and the below would give us
>the usefulness we want and the security we want.  (I don't think
>the below would work with Van Jacobsen's traceroute 1.2)

>On Wed, 21 Aug 1996, Vadim Antonov wrote:

>> On itself, LSRR is a godsend to hackers (i can think of about
>> a dozen of very nasty attacks using general LSRR).  The only
>> useful application for it is traceroute.
>> Why don't router vendors provide an option to turn it
>> off for everything but ICMP ECHO?
>> --vadim

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