Re: [idn] length restrictions on IDN label

[Soobok Lee <lsb@postel.co.kr>]

Mark.Andrews@isc.org wrote:

>
>	Repeat after me: "HOSTNAME != DOMAIN NAME".
>
Everyone knows that here. :-)
Applications , in general, deal with hostnames (smtp?), not abstact
domain names (nslookup,dig?).
It has been clear that i am saying in the context of appliations's
hostname label buffer space problems.

>
>	Hostnames are a subset of domain names (ignoring hostnames
>	that are larger that 253 and hence not supported by the
>	DNS).  If you are only dealing with hostnames then you
>	should be rejecting domain names that are not legal hostnames.
>
Yes.

>	Anything reading unsanitized domainnames has to expect a
>	strings bigger than 255 when converted to RFC 1034 presentation
>	format.
>
You repeated this twice. And i had agreed.

>
>	Some implementations of gethostbyaddr() do this sanitization
>	for you.  This was also one of the reasons IDNs are converted
>	to and from ACSII.  ToUnicode should be perform outside of
>	gethostbyaddr().  Moving it inside of gethostbyaddr() is a API
>	change.
>
True.

Soobok Lee

>
>	Mark
>
>  
>
>>asm/param.h:#define MAXHOSTNAMELEN 64 /* max length of hostname */
>>imap/mail.h:#define NETMAXHOST 65
>>imap/mail.h: char host[NETMAXHOST]; /* host name (may be canonicalized) */
>>imap/mail.h: char orighost[NETMAXHOST]; /* host name before
>>canonicalization */
>>lwres/netdb.h:#undef NI_MAXHOST
>>lwres/netdb.h:#define NI_MAXHOST 1025
>>mozilla/plresolv.h:#define PL_RESOLVE_MAXHOSTENTBUF 1024
>>protocols/timed.h: char tsp_name[MAXHOSTNAMELEN];
>>rpcsvc/rusers.h:#define RUSERS_MAXHOSTLEN 257
>>rpcsvc/rusers.x:const RUSERS_MAXHOSTLEN = 257;
>>rpcsvc/rusers.x: string ut_host<RUSERS_MAXHOSTLEN>; /* host user logged
>>on from */
>>rpc/types.h:#ifndef MAXHOSTNAMELEN
>>rpc/types.h:#define MAXHOSTNAMELEN 64
>>w3c-libwww/wwwsys.h:#ifndef MAXHOSTNAMELEN
>>w3c-libwww/wwwsys.h:#define MAXHOSTNAMELEN 64 /* Any better ideas? */
>>X11/Xos_r.h: char h_name[MAXHOSTNAMELEN];
>>
>>
>>    
>>
>>>	As I said what you are talking about is NOT new.  These
>>>	issues have existed for years.
>>>
>>>      
>>>
>>yes, for presentation formats, it is not new. But for protocol elements,
>>it is new. isn't it ?
>>
>>Soobok Lee
>>
>>
>>
>>    
>>
>--
>Mark Andrews, Internet Software Consortium
>1 Seymour St., Dundas Valley, NSW 2117, Australia
>PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews@isc.org
>  
>