[erlang-questions] is inet:gethostbyname( IP ) correct?

Roberto Aloi <>
Wed Oct 14 12:20:34 CEST 2009


At the end of my last mail you have the references.
Regards,

Roberto Aloi
Erlang Training and Consulting Ltd.
http://www.erlang-consulting.com
http://aloiroberto.wordpress.com

Robert Raschke wrote:
> This is part of the IP address spec (not sure where to look to find it,
> though). I've seen addresses specified like this on and off in various
> locations on a wide variety of OSes, for example in a /etc/hosts file you
> can write:
>
> localhost  127.1
>
> Robby
>
> On Tue, Oct 13, 2009 at 8:06 PM, caio ariede <> wrote:
>
>   
>> Interesting case.
>>
>> The result doesn't appear to be an issue, but a feature of the
>> gethostbyname
>> original implementation, in C code.
>>
>> You get the same result, testing with PHP:
>>
>> $ php -r 'var_dump(gethostbyname("12.27"));'
>> string(9) "12.0.0.27"
>>
>> And other interesting results:
>>
>> $ php -r 'var_dump(gethostbyname("255.2.256"));'
>> string(9) "255.2.1.0"
>>
>> But I can't see where it's really useful.
>>
>> Caio Ariede
>> http://caioariede.com/
>>
>>
>> On Tue, Oct 13, 2009 at 3:15 PM, Garry Hodgson <
>>     
>>> wrote:
>>>       
>>> recently, a bug in my code caused us to pass a string
>>> representing a floating point number to inet:gethostbyname().
>>> i would have expected it to return an error, but instead it
>>> returned an ip address, but one that made no sense to me:
>>>
>>> 1> inet:gethostbyname( '12.27' ).
>>> {ok,{hostent,"12.27",[],inet,4,[{12,0,0,27}]}}
>>>
>>> so my question is, is this behavior correct, and if so, what
>>> exactly does it mean that a lookup of '12.27' maps to '12.0.0.27'?
>>>
>>> thanks
>>>
>>> --
>>> Garry Hodgson
>>> Lead Member of Technical Staff
>>> AT&T Chief Security Office (CSO)
>>>
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>
>   



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