With the right capabilities (NA and NM) you can run PING.NET.SYS and it will prompt you for the IP address, packet size and number of packets you wish to send, or you can simply PING.NET.SYS "nnn.nnn.nnn.nnn" (the IP address) and it will continually ping until you hit Ctrl-y.

A much more feature rich ping (includes ping-by-name capabilities if you have a DNS server configured) is available as an item in nettool.net.sys.