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SubjectRe: ping to broadcast address: permission denied?
If you would have actually tried first to see if you could verify your
claim, maybe you wouldn't have made such a fool of yourself.

Observe:

utopia:~$ ls -al /bin/ping
-r-sr-xr-x 1 root bin 17412 Feb 18 1995 /bin/ping
utopia:~$ ifconfig eth0
eth0 Link encap:10Mbps Ethernet HWaddr 00:00:C0:F0:75:0E
inet addr:206.84.74.11 Bcast:206.84.74.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:927673 dropped:0 overruns:0
TX packets:0 errors:0 dropped:620623 overruns:2
(yeah ill upgrade ifconfig sometime :)
Interrupt:10 Base address:0x6000

utopia:~$ ping 206.84.74.255
PING 206.84.74.255 (206.84.74.255): 56 data bytes
ping: sendto: Permission denied
ping: wrote 206.84.74.255 64 chars, ret=-1
ping: sendto: Permission denied
ping: wrote 206.84.74.255 64 chars, ret=-1

--- 206.84.74.255 ping statistics ---
2 packets transmitted, 0 packets received, 100% packet loss
Obviously this is running as root...
And pinging the broadcast address is still failing...
Any network gurus know why?

PS
Maybe you could have noticed his '#' prompt... sure, thats doesn't
necessarily imply that he is root, but its usually the case.

On Fri, 7 Mar 1997, Bryn Paul Arnold Jones wrote:

> On Fri, 7 Mar 1997, Paul Slootman wrote:
>
> > Niemi@linux.wauug.org wrote:
> > >
> > >I have fetched, compiled, and made available Trygve Gudmundsen's
> > >Linux-modified version of Eric Wassenaar's excellent "ping" program. It is
> > >all sitting on on wauug.erols.com in "/pub/net/wassenaar-ping". As Trygve
> > >mentioned his site was about to be down for 5 days I figured this could be
> > >a useful service 8^)
> >
> > I've picked up this version, compiled it, but it still doesn't
> > do what I'd hoped (I had already expected it wasn't a ping code
> > problem).
> >
> > The problem is this:
> >
> > I'm on a subnetted B-class network (141.93.34.0, netmask 255.255.255.0).
> > This all works fine, however I cannot ping the broadcast address (which
> > is 141.93.34.255). Ping says:
> >
> > # ./ping 141.93.34.255
> > PING 141.93.34.255: 56 data bytes
> > sendto: Permission denied
> > no reply from 141.93.34.255 within 1 sec
> > sendto: Permission denied
> >
> > ---- 141.93.34.255 PING Statistics ----
> > 2 packets transmitted, 0 packets received, 100% packet loss
> >
>
> This would be a setuid root problem, ie it isn't. Does it work if you run
> the binary as root ?
>
> > This works perfectly from a Solaris 2.5 system on the same network...
> > I tried tracing this into the kernel, but at a certain point I get
> > lost. It's definitely sendto() that returns -1 EACCES, according to
> > strace.
> >
>
> Yep, the solaris binary will be setuid root.
>
> > Same thing when pinging the loopback broadcast address 127.255.255.255,
> > so it doesn't look like it's a subnetting problem.
> >
>
> Try setting the setuid bit on the binary:
>
> chown root.root ping; chmod 4555 ping
>
> It should now look like:
>
> -r-sr-xr-x 1 root root 12272 Jan 31 22:32 ping*
> ^ setuid bit.
>
> > Anyone know what the problem is? Even better, what the solution is?
> > Vanilla 2.0.29.
> >
> >
> > Paul Slootman
> > --
> Bryn
> --
> PGP key pass phrase forgotten, \ Overload -- core meltdown sequence
> again :( and I don't care ;) | initiated.
> / This space is intentionally left
> | blank, apart from this text ;-)
> \____________________________________
>


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