in this case it's octal in action. leading 0 causes the libc calls to expect non-decimal input (octal or hex, depending on what comes next).
a few organizations, FWIW, insist on writing decimal dotted quads zero padded (e.g. 192.168.19.20 becomes 192.168.019.020) for evan formatting. this barfs various tools and scripts that (not surprisingly) expect octal if they see a leading 0 and then barf on the non-octal-ness of the data OR get it wrong.
something to be aware of, especially if you script batch processing of inputs that include lists of IPs.
a few organizations, FWIW, insist on writing decimal dotted quads zero padded (e.g. 192.168.19.20 becomes 192.168.019.020) for evan formatting. this barfs various tools and scripts that (not surprisingly) expect octal if they see a leading 0 and then barf on the non-octal-ness of the data OR get it wrong.
something to be aware of, especially if you script batch processing of inputs that include lists of IPs.