FQDN
John Hascall
john at iastate.edu
Sat Jul 26 17:39:33 UTC 2003
> phaniraj ranganath wrote:
> >
> > I want to know why the FQDN cann't be more than 256 characters
> > & the name at any node in Internet Domain name space cann't be more
> > than 63 characters?
>
> The length limit is 255 not 256 I believe.
>
> The reason is that rfc1034 says so, read the rfc's for more background,
> but it says "to ease implementation".
>
> > Is there any restriction in the number of levels
> > in Internet i.e. from root servers how many levels can the structure
> > of internet span?
>
> As far as I know only the implied limit from the length restrictions
> which I make 128 labels of one character.
>
> However you would need to check the resolution algorithms to see if this
> would break the resolvers in common use, as I suspect some might give up
> before they had got to resolving a name involving substantially more
> levels than possible. It is possible one of the RFCs implies a lower limit.
Experimentally, stupidly long names seem to work in at least some cases:
% nslookup
> a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a
Server: netreg-1.ait.iastate.edu
Address: 129.186.1.16
Name: a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a.a
Address: 129.186.1.16
Why somebody would want to actually use such a thing escapges me though,
as the whole point of DNS is that names are easier than numbers.
John
More information about the bind-users
mailing list