[clug] Re: Determining availability of a remote machine

Kim Holburn kim.holburn at anu.edu.au
Thu Apr 3 19:38:16 EST 2003

At 5:47 PM +1000 2003/04/02, Jepri wrote:
>On 2003.04.02 17:43, Steve Jenkin wrote:
>>'traceroute' relies on the proper intermediate handling of expired
>>'time to
>>live', not ICMP ECHO (ping).
>>>From my (linux) manpage:
>>        -I     Use ICMP ECHO instead of UDP datagrams.
>>       -p     Set  the  base  UDP  port  number  used  in  probes
>>              (default is 33434).  Traceroute hopes that  nothing
>>              is  listening on UDP ports base to base + nhops - 1
>>              at the destination host (so an  ICMP  PORT_UNREACH-
>>              ABLE  message  will  be  returned  to terminate the
>>              route tracing).  If something  is  listening  on  a
>>              port  in the default range, this option can be used
>>              to pick an unused port range
>>... .then listening for an  ICMP  "time  exceeded" reply from a
>>Would be nice if it would use an designated TCP port, would work just
>>as well
>>and could be 'jiggled' to go through various firewalls. [tcp:80/http
>>is an
>>obvious default choice]
>This is already part of the ping standard.  Try looking in your /etc/services file.  It's almost always commented out.

Exactly what is it you're talking about?  What is part of the ping standard?  /etc/services has udp and tcp ports.  What has that to do with ping?

>ping-pong       3010/udp        # Telerate Workstation
>lsp-ping        3503/tcp        # MPLS LSP-echo Port
>lsp-ping        3503/udp        # MPLS LSP-echo Port
>#                          Ping Pan <pingpan at juniper.net>
>pds             9595/tcp        # Ping Discovery Service
>pds             9595/udp        # Ping Discovery Service

Also your email has an odd header:

Cc: Warwick Mitchell <wmitchell at shed.org.au>
Cc: Linux user group <linux at samba.org>

I thought the standard was to use header continuation lines:
Cc: Warwick Mitchell <wmitchell at shed.org.au>,
   Linux user group <linux at samba.org>
My mail client doesn't hand;e this well.  (Not that that means a lot).

Kim Holburn 
Network Consultant - Telecommunications Engineering
Research School of Information Sciences and Engineering
Australian National University - Ph: +61 2 61258620 M: +61 0417820641
Email: kim.holburn at anu.edu.au  - PGP Public Key on request

Life is complex - It has real and imaginary parts.
     Andrea Leistra (rec.arts.sf.written.Robert-jordan)

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