[EMAIL PROTECTED] wrote: > Well if you use raw utf-8 today int the DNS you are limited to > 63 octets per label. 255 octets for a domain name. As long as > you continue to use the same label encoding you are limited to > 63 octets. YMMV at levels other than the DNS. > Sure. If the limit may vary at levels (applications)other than the DNS, the utf8 labels may exceed 63 octets in appliction protocol formats (not for display) and the implementors should reserve enough buffer spaces for ToUnicoded(ACE) utf8 labels. This really matters because many programmers favor utf8 as internal representation format of unicode strings for its ascii compatibility.
Most applications programmer have been reserving 256 bytes for any LDH FQDN buffer space . But that convention should be changed to cover the cases of long utf8 IDN FQDN which may be 3 or 4 times longer than 256 octets. So, 1024 or 768 bytes are good. But those utf8 FQDN cannot be put into single UDP packet of DNS response/query. This will constrain future DNS protocol update efforts around utf8 supports in wire format. TOday's long iDNs may be one of the obstacles in the way to the effort. If this warning is neglected by application programmers, some remote malicious crackers will send to users' applications long ACE IDNs manufactured to cause buffer overflow errors when toUnicoded and seaze control of the machine. Soobok Lee
