puzzling behaviour with leading zeros about ipaddress HOT 3 CLOSED

Hello. Firstly, you can use toAddress to get an exception. It is the same as getAddress but throws exceptions for invalid addresses instead of returning null. The exception will have a message indicating the issue.

Secondly, this behaviour is explained somewhat here, and somewhat here.

In summary, when you put a 0 in front of an IPv4 address value, it is, by default, considered to be octal. This is known as BSD-style format for IPv4. It originated with a routine known as inet_aton. If you put a similar address in your browser, http://89.000.074.209, you can see it is changed to http://89.0.60.209/. That is because 074 in octal is 60 decimal.

However, in your case, you used 094 octal, which is an invalid value, since octal does not allow '9' digits. So it is an invalid address. If you put http://89.000.094.209 in your browser you can see it is no longer considered an IPv4 address, and will likely do a search with it as a string.

You can use search parameters with this library to treat it as a decimal value. Example here of using IPAddressStringParameters. Use the setting allow_inet_aton_octal.

from ipaddress.

If you have further questions, feel free to ask.

from ipaddress.

Thanks for the explanation!

from ipaddress.