Ping is a tool that helps to verify IP-level reachability. The ping command can be used to send an ICMP echo request to a target name or IP address. First, ping the IP address of the target host to see if it responds because this is the simplest test. If that succeeds, try pinging the name. Ping uses Windows Sockets-style name resolution to resolve the name to an address; therefore, if pinging by address succeeds but pinging by name fails, the problem lies in name resolution, not network connectivity. Type ping -? to see what command-line options are available. Ping allows you to specify the size of packets to use, how many to send, whether to record the route used, what TTL value to use, and whether to set the don't fragment flag. See the PMTU discovery section of this document for details on using ping to manually determine the PMTU between two computers.
The following example illustrates how to send two pings, each 1450 bytes in size, to address 10.99.99.2:
C:\>ping -n 2 -l 1450 10.99.99.2
Pinging 10.99.99.2 with 1450 bytes of data:
Reply from 10.99.99.2: bytes=1450 time<10ms TTL=32
Reply from 10.99.99.2: bytes=1450 time<10ms TTL=32
Ping statistics for 10.99.99.2:
Packets: Sent = 2, Received = 2, Lost = 0 (0% loss),
Approximate round trip times in milliseconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms
By default, ping waits one second for each response to be returned before timing out. If the remote system being pinged is across a high-delay link, such as a satellite link, responses could take longer to be returned. The -w (wait) switch can be used to specify a longer time-out. Computers using IPSec may require several seconds to set up a security association before they respond to a ping.
