Ping = online check?

Question

Ping = online check?

Answer 1

If you ping it and it's firewall us working right then it should come back as unreachable

Answer 2

Actually most organizations do not care about the Ping Command because its threat have been avoided by current products so usually you should get a reply from the pinged IP Address. But if at times you dont get the reply and you know that the machine you are pinging is alive that means, the router has blocked the ICMP Requests that is the PIng Request.



You can use other freely available software to really find out whether the computer holding the IP address is alive. You can search for a couple of them from http://www.download.com



BYE

Imtiyaz

Answer 3

Try the ping when you know the PC is in fact active and online. If it does come back OK, then you can be reasonably sure that a ping timeout indicates the PC is offline.



The real question is, how do you know the PC's true IP address? Most ISPs and home-based routers use Network Address Translation and other techniques that spoof or otherwise hide either your true IP address or the target PCs. Also, IP addresses are usually dynamically assigned (via DHCP) when the PC connects to the ISP, so it might get one IP address one day, but a different IP address another day. You might have to request a permanent IP address from the ISP in order to guarantee that you're pinging the right PC.

Answer 4

First of all ping can be blocked from passing through a network device or the PC itself can be configured to reject the ping traffic (ICMP traffic). so not receiving a ping reply from a device doesn't necessarily means it is not online unless we know for sure that ping is allowed both on the device and through the network.



On the other hand when you receive a destination unreachable reply, it usually means that a router or a network device in the path is unable to determine where the destination device is.



hope this helps..

Answer 5

Dear Ray.........



U can also use trace route for the same......So u can know ISP router block or not also u know where is blocking.

Answer 6

if pc have firewall or he blocked ur ip or ip range in firewall....



u will receive dead ping or "Destination host unreachable"

Answer 7

Ping only gets an ICMP echo response from the network interface... it doesn't prove the PC is actually up and running (for instance... I've seen hung systems, both PC and not PC, where the system kept responding to ping even though it was blue screened, hung 'dead in the water' or rebooting.



You only see the response if every network component between you and the PC allows your ICMP echo request to get to the compuetr and the ICMP echo response to get back to you. Any firewall in the way can be set to block ICMP traffic... or any type of ICMP traffic... in which case you'll never get a response.



If you get 'destination host unreachable' it means you've specified a host that you don't have any way to reach. For instance, you've not got a network connection. For another instance, your ISP can't find a route to the target because you specified a wrong IP address. For instance your ISP can't find a route to the target because something en-route is broken and there is no way round the blockage. Final for instance, you've specified an IP address that is not allowed to be routed (one of the private non-routable subnets like 192.168.100.000).



Any other ways to check if a PC is online? It depends what the PC is running... and where it is... and what lies between you and it. Firewalls can be set to block or permit specific protocols, so possibly anything you try will fail to get through. You can try telnet... which will be refused by a 'normal' PC running windows but refusal tells you it's there. Same for FTP. You could try SNMP. You could try telnet to other specific ports.



Or you could call someone up at the site with the PC and ask them to check.



All you can say for sure is... if you get a response from the PC then it's active on the net. If you don;t get a response it may be because it's off line or it may be because there is a block on the way there.