Testing connections by using ping

 

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The ping command helps to verify IP-level connectivity. When troubleshooting, you can use ping to send an ICMP echo request to a target host name or IP address. Use ping whenever you need to verify that a host computer can connect to the TCP/IP network and network resources. You can also use ping to isolate network hardware problems and incompatible configurations.

It is usually best to verify that a route exists between the local computer and a network host by first using the ping command and the IP address of the network host to which you want to connect. Try pinging the IP address of the target host to see if it responds, as follows:

ping IP_address

You should perform the following steps when using ping:

1. Ping the loopback address to verify that TCP/IP is installed and configured correctly on the local computer.

   ping 127.0.0.1

2. Ping the IP address of the local computer to verify that it was added to the network correctly.

   ping IP_address_of_local_host

3. Ping the IP address of the default gateway to verify that the default gateway is functioning and that you can communicate with a local host on the local network.

   ping IP_address_of_default_gateway

4. Ping the IP address of a remote host to verify that you can communicate through a router.

   ping IP_address_of_remote_host

The ping command uses Windows Sockets-style name resolution to resolve a computer name to an IP address, so if pinging by address succeeds, but pinging by name fails, then the problem lies in address or name resolution, not network connectivity. For more information, see Troubleshooting hardware addresses by using arp

If you cannot use ping successfully at any point, confirm that:

• The computer was restarted after TCP/IP was installed and configured.
• The IP address of the local computer is valid and appears correctly on the General tab of the Internet Protocol (TCP/IP) Properties dialog box.
• IP routing is enabled and the link between routers is operational.

You can use different options with the ping command to specify the size of packets to use, how many packets to send, whether to record the route used, what Time-to-Live (TTL) value to use, and whether to set the "don't fragment" flag. You can type ping -? to see these options.

The following example illustrates how to send two pings, each 1,450 bytes in size, to IP address 172.16.48.10:

C:\>ping -n 2 -l 1450 172.16.48.10
Pinging 172.16.48.10 with 1450 bytes of data:

Reply from 172.16.48.10: bytes=1450 time<10ms TTL=32
Reply from 172.16.48.10: bytes=1450 time<10ms TTL=32

Ping statistics for 157.59.8.1:
    Packets: Sent = 2, Received = 2, Lost = 0 (0% loss),
Approximate roundtrip times in milli-seconds:
    Minimum = 0ms, Maximum =  10ms, Average =  2ms

By default, ping waits 1,000 ms (1 second) for each response to be returned before displaying the "Request Timed Out" message. If the remote system being pinged is across a high-delay link, such as a satellite link, responses may take longer to be returned. You can use the -w (wait) option to specify a longer time-out.