On Tue, Oct 24, 2017 at 10:57:42PM +0700, Robert Elz wrote: > | 3. syntactically correct numerical IPv4 addresses contain digits and dots > > Which is exactly what a domain name can contain. The only reason that > IP addresses (in textual format) are not currently valid domain names, is > that there are currently no top level domains with all numeric labels. > But who knows what ICANN will create next week?
At least inet_pton parses a numerical IPv4 addresses without any dots. Add the implicit search domain from /etc/resolv.conf and you can get names for gai that contains purely digits and are still ambigious on whether they should be resolved via DNS or not. Joerg
