ICMP support is implemented for both IPv4 and IPv6 addresses, using the operating system's host name resolution (via resolve-host ):
icmp

<icmp> ( host -- icmp )


IPv4 addresses, with no host name resolution:
icmp4

<icmp4> ( host -- icmp4 )


IPv6 addresses, with no host name resolution:
icmp6

<icmp6> ( host -- icmp6 )