🚀 go-pugleaf

In article <336d1cf7.52504565@news.demon.co.uk>
   peter@pmorton.demon.co.uk (Peter Morton) writes:
> I'm trying to find the maximum length allowed for a domain name -
> presuming there is one?  I'm suffering from RFC overload on this one
> and although I expected it to be in the "Internet Encyclopedia",  a
> few searches haven't revealed the information (and as it's a 7Meg file
> I don't want to download it!).

As far as I'm aware there isn't a maximum length, except that of 
practicality, if it's too long who'd want to type it? A quick look
through DNS and Bind, doesn't reveal any indication of a maximum allowable
length either.

> Demon announced a while back that 16 character fields were acceptable
> for our host names,  but what about the "Demon" field (8?), the com,
> edu, ac, field (3?) and the country, aus, uk (3?).

The last 1/2 fields of your domain are chosen from a limited range of 
fixed options depending on what you domain is:
eg. .com for commercial sites .co.uk for uk based companies .org for 
non-profit making organizations etc.
The rest can in theory be any length, although if it's unfeasibly long or
short with no justification you may have trouble registering it with
the internic /* assuming a .com or .org */

> Also, are there just the four fields allowed,e.g.
> pmorton.demon.co.uk  or is this expandable further - 
> subdomain.pmorton.demon.co.uk ?

You can expand it as far as you like, as an obvious example 
www.ka9q.demon.co.uk
although again think if you actually need to.

> Any pointers appreciated. Thanks.

comp.protocols.domains /* ? */
DNS and BIND O'Reilly
RFC's 1035 1183 882 883 1034
disview domain

> Btw - all this effort is just to determine the string variable size
> required for a sockets exercise.  I could, and have, set it to some
> figure which will handle the immediate data to hand but would rather
> have it determined "properly".

Have a look at the ka9q domain server code then or the jnos one
RFC 1035 is the more relevant RFC for this exercise, equally have a look
at the code for UNIX BIND.

-- 
Slainte                                         ____
Giolla Decair                                   \  /__
"Broken inside now our hearts lost forever       \X  /
 Can't replace the fear or the thrill of the chase"\/