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Well, this is a new one on me!

Community Veteran
Posts: 13,919
Thanks: 514
Fixes: 7
Registered: 01-08-2007

Well, this is a new one on me!

Windows 7 Home Premium:

Spot the rather strange behaviour.
First IP is a computer I know is on and connected via WiFi as the SO is using it.
Second IP is a computer that is turned off (it's my netbook and its right next to me with no power on at all). Before anyone like James suggests this may be the fault with my router, the netbook connects by Wifi too and while its off thats not even possible. It also hasn't been used a a couple of days (oh and I didn't have it when the first few routers fried either!)
Anyway this is clearly an MS bug because if you look at the picture, my desktop machine has been responding to its own outbound pings saying that the host is unreachable and then counts the packet as returned. Thus the 3 lost packets to the SOs computer upstairs were counted even though they were not returned.
Anyone else had this?
I need a new signature... i'm bored of the old one!
3 REPLIES
kmilburn
Grafter
Posts: 902
Thanks: 2
Registered: 30-07-2007

Re: Well, this is a new one on me!

It's not a bug,  Destination Host Unreachable is a valid ICMP return packet (hence no loss), and came from  the device with the address 192.168.0.2  (which I take it is your machine).
This response usually occurs because  the other device didn't respond to the ARP request,  which is supposed to return the MAC address  that needs to be used. 
The SO's machine responded eventually, which is why the last ping was successfull (still took over a second though!), with the netbook being off it couldn't respond, so it's no surprise it's unreachable.
You can change the number of pings done to see how well the wireless is performing...
Community Veteran
Posts: 13,919
Thanks: 514
Fixes: 7
Registered: 01-08-2007

Re: Well, this is a new one on me!

You're not seeing the point..
Look at the statistics for the packet loss - 0% loss, 100% received. This never happened under WinXP, Me, 98.. unless there was a valid packet returned with a time in ms it was counted as lost. Win7 counts non returned packets as returned and not lost.
Thats the point I'm trying to make. Ping is effectively now useless as it gives incorrect stats.
I need a new signature... i'm bored of the old one!
kmilburn
Grafter
Posts: 902
Thanks: 2
Registered: 30-07-2007

Re: Well, this is a new one on me!

If the only piece of information you care about is the number of received/lost packets, I can see your point,  but A destination host unreachable message is a response.
There are other responses which could also be received while the machine you wanted didn't respond  (e.g. TTL Expired).
And yes,  this was a definite change in behaviour in Windows 7 (if not Vista) but,  while you may not consider it useful,  it is to some of us!