Re: ping to broadcast address: permission denied?
Ed Saffle (ed@UU.NET)
Fri, 07 Mar 1997 14:30:46 -0500
That's strange, it works just fine for me. It just complains a
lot about duplicate answers which is correct since it is in fact
getting muliple answers back for each sequence number. Maybe you
both just need a newer version of ping?
Illuminati Primus writes:
> 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 Tryg
>ve
> > > >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 ;-)
> > \____________________________________
> >
>