# ping -b xxx.xxx.xxx.255

porous · 10-13-2003, 11:01 AM

hi

in our college lab we have a network of win2k machines ,
and some machines with rh9 . the sever is win2k
the lan is a swithched one.

# ping -b xxx.xxx.xxx.255

when i give the command only the linux machines which are up
reply to the broadcast request .
no windoze machines reply to the broadcast machine
can anyone shed some light on this

thx

--------------------------------------------------------------

"look straight and you wont miss the pole ..."

hw-tph · 10-13-2003, 12:30 PM

Disclaimer: I'm grabbing this out of thin air, I have no evidence whatsoever, haven't even tested, and I'm not 100% of the inner workings of ping responses on Windows vs Linux boxen...but here's my little thought:

Windows machines use ICMP ping while Linux and most traditional UNIXes use UDP ping, maybe that's your problem? That the Windows boxen won't reply to UDP ping for some reason? Perhaps some configuration in the switch.

Anyway, I'm just rambling here.

hw

Rab22 · 10-13-2003, 12:34 PM

/proc/sys/net/ipv4/icmp_echo_ignore_broadcasts

I believe once this is set to 1 it won't reply to ICMP broadcast messages simliar to that of the Win2k machines. I believe that this is typically Windows machines do not respond to broadcast ICMP messages where as Linux defaultly does.