"matches an ip address" is a vague enough specification that of course people fail.
Is it what `inet_addr` accept? In that case, "1", "0x1", "00.01", "00000.01", and more are all ip addresses. `ping` accepts all of em anyway.
Is a valid ipv6 address one with the square brackets around it? Is "::1" a valid ip address? What about "fe80::1%eth2"? ping accepts both of these on my machine (though probably not on yours, since you probably don't have an eth2 interface)
square brackets around an IP address predates IPv6, it was/is? used to bypass DNS lookups and some (very) old programs required IP addresses inside [...] otherwise they were assumed to be a domain name with all the rules that implied.
Comments
"matches an ip address" is a vague enough specification that of course people fail.
Is it what `inet_addr` accept? In that case, "1", "0x1", "00.01", "00000.01", and more are all ip addresses. `ping` accepts all of em anyway.
Is a valid ipv6 address one with the square brackets around it? Is "::1" a valid ip address? What about "fe80::1%eth2"? ping accepts both of these on my machine (though probably not on yours, since you probably don't have an eth2 interface)
square brackets around an IP address predates IPv6, it was/is? used to bypass DNS lookups and some (very) old programs required IP addresses inside [...] otherwise they were assumed to be a domain name with all the rules that implied.