IPv4 address validation

I ran into an issue where ods-signerd was unable to parse an A record in the unsigned zone file that looked like this:

example IN A 127.001.001.001

It appears that the leading zeros were an issue.

If possible, the zone file parsing system should be more tolerant of these sorts of quirks, as not all unsigned zone files are manually maintained, but are often generated using user input, and the above IP address format would pass through the vast majority of sanity filters applied to user input.