On Mar 16, 2016, at 10:07 AM, Lee <ler...@gmail.com> wrote:
>
> The last time I tried the cygwin ping program it didn't return a
> failure status
It does if you don’t Ctrl-C out of it. So, if you’re using it from a script,
you just ask for one packet:
# ping does.not.exist 1 1
ping: unknown host does.not.exist
# echo $?
1
Note my fine new # prompt, indicating an admin shell, which has been required
for Cygwin ping from the very beginning[1] due to the restrictions on raw
sockets added in Windows XP SP2. Windows ping gets around this by special
dispensation of the kernel.[2]
If you want to say Cygwin ping is “useless” because of that, blame Microsoft
for not allowing ICMP raw sockets for normal users [3] or for not reinventing
suid bits correctly. (UAC = not correct.)
Older Linuxes and some modern Unixes set the suid bit on the ping program to
get around this, and newer Linuxes use getcap/setcap to give the ping program
the right to use raw sockets so they don’t need u+s.[4]
[1] https://cygwin.com/ml/cygwin-apps/2005-01/msg00124.html
[2] It loads IPHLPAPI.DLL at run time in order to call IcmpSendEcho()
[3] https://goo.gl/o25d6U
[4] http://linux.die.net/man/8/setcap
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