what's a valid domain name?

pyh at mail.nsbeta.info pyh at mail.nsbeta.info
Sat Jan 29 05:30:51 UTC 2011

Barry Margolin writes: 

> In article <mailman.1559.1296265826.555.bind-users at lists.isc.org>,
>  pyh at mail.nsbeta.info wrote: 
>> I  googled and found this: 
> It's on the Internet, so it must be true. :) 
>>     * A domain name can be up to 63 characters long plus a dot plus the 
>> characters used to identify the top-level domain (i.e "com", "info", "biz", 
>> etc.
>>     * Valid characters in a domain name include letters, numbers and 
>> hyphens "-". The domain name must start and end with a letter or number.  
>> So, for this domain name of   
>> "www.xyxyxyxyxyxyxyxyxyxyxyxyxyxyxyxyxyxyxyxyxyxyxyxyxyxyxyxyxyxyxyxy.com" 
>> whose size is larger than 64, is not a valid domain name?  
>> And is there a RFC item for a valid domain name? 
> RFC 1035 section 3.1 says: "To simplify implementations, the total 
> length of a domain name (i.e., label octets and label length octets) is 
> restricted to 255 octets or less." 
> The length of each label within a domain name is limited to 63 
> characters. 

Thanks for the kind info. 


More information about the bind-users mailing list