what's a valid domain name?

[John Wobus]

To add to the story, I added a rule to our DNS administration
system that we'll only allow hostnames that include
at least one alphabetic.

John

On Feb 4, 2011, at 11:26 AM, John Wobus wrote:

> So 10.14.22.11 is a legal hostname, right?
>
> We had a recent experience where our DNS administration
> system allowed someone to insert in a CNAME record that
> resembled this:
>
> www.example.com. CNAME 10.14.22.11.
>
> A fascinating thing about this is that my computer/browser could
> take me to www.example.com just fine.
>
> John Wobus
> Cornell
>
>
>
> On Jan 30, 2011, at 7:30 AM, pyh at mail.nsbeta.info wrote:
>
>>
>> From RFC 1123
>>
>>       One aspect of host name syntax is hereby changed: the
>>       restriction on the first character is relaxed to allow either a
>>       letter or a digit.  Host software MUST support this more
>> liberal
>>       syntax.
>>
>>
>>
>>
>> pyh at mail.nsbeta.info writes:
>>
>>> Joseph S D Yao writes:
>>>
>>>>
>>>> The labels must follow the rules for ARPANET host names.  They must
>>>> start with a letter, end with a letter or digit, and have as
>>>> interior
>>>> characters only letters, digits, and hyphen.  There are also some
>>>> restrictions on the length.  Labels must be 63 characters or less.
>>>>
>>>
>>> A label must start with a letter? oh I don't think so.
>>> How about these domains which all have huge DNS traffic?
>>>
>>> 163.com
>>> 126.com
>>> 51.com
>>> 56.com
>>>
>>> yes 163.com is a domain name but "163" also can be treated as a
>>> label for
>>> domain "com.", is it?
>>>
>>> Thanks.
>>>
>>> Regards.
>>> _______________________________________________
>>> bind-users mailing list
>>> bind-users at lists.isc.org
>>> https://lists.isc.org/mailman/listinfo/bind-users
>> _______________________________________________
>> bind-users mailing list
>> bind-users at lists.isc.org
>> https://lists.isc.org/mailman/listinfo/bind-users
>