SUMMARY: weird ping results

From: @att.att.com:ken@alphlz.alph.att.com
Date: Wed Sep 04 1991 - 11:09:45 CDT


A few days ago I asked for help in figuring out what the
following ping session ment:

> stpserver1# ping -s -Rv sluggo
> PING sluggo: 56 data bytes
> ICMP Host Unreachable from gateway 192.20.31.254
> for udp from bstpserver1 (192.0.2.20) to mcw (120.0.0.244) port 682
> ^C
> ----mcw PING Statistics----
> 1070 packets transmitted, 0 packets received, 100% packet loss
> stpserver1#

I now know why I got the message: I didn't pay attention to
the FM. The -v option reports *all* the ICMP messages it
sees.

Thanks to:
        Neil W Rickert <rickert@ics.niu.edu>
        leonid@amil.co.il (Leonid Rosenboim)
        stern@bitatron.Eng.Sun.COM (Hal Stern - Consultant)

As far as why ping statisics are being reported for 'mcw'
instead of 'sluggo', this is a bug in the ping program.

Two letters discussed this:

>From: allegra!mp (Mark Plotnick)
>
>ping calls gethost* routines a few times and neglects the fact
>that they return a ptr to a static buffer that can get overwritten
>during subsequent calls. The fix is to copy the results of
>gethostbyname() into a buffer rather than just saving the ptr.
>If you have source I can give you a 2-line fix.

>From: Joerg.Hertzer@rus.uni-stuttgart.de (Joerg Hertzer)
>
>That's a bug in the ping program.
>I observed it myself several times when I pinged to a
>host that is written near the end of my /etc/hosts file.
>It helped to modify the /etc/hosts in a way,
>that the pinged host is near the beginning of /etc/hosts.
>May be you should do the same with the entrys
>of involved routers.
>Note that under same circumstances the time information from 'ping -s'
>is wrong too!

Many thanks to all that responded!

-----

        Ken Seefried ken@alphlz.att.com
        AT&T Communications uunet!att!alphlz!ken
        Alpharetta, GA +1 404 750 7152



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