Subject: WG Action - ACCEPT [LL4] No Examples of Applications

From: Erik Guttman <[email-masked]>
Date: Tue, 13 May 2003 10:33:30 +0200 (CEST)

See http://www.spybeam.org/ll4.html and 
    http://www.spybeam.org/ll5.html for details about the issues.

Action:
  [LL4]   Accepted 
  [LL5]   Closed

Accepting the text supplied by Bernard Aboba satisfies both LL4 and LL5
considerations.

Implication:
Create a new introduction section with the text:

Use of linklocal IPv4 addresses in off-link communication is likely to
cause application failures. This can occur within any application that
includes embedded addresses, if an LLv4 addresses is embedded when
communicating with a host that is not on the link. Examples of
applications that include embedded addresses are found in [RFC3027]. 
This includes IPsec, Kerberos 4/5, X-Windows/Xterm/Telnet, FTP, RSVP,
SMTP, SIP, Real Audio, H.323, and SNMP. 

In order to prevent use of LLv4 addresses in off-link communication, the
following cautionary measures are advised:

a. Routable addresses should be used within applications whenever they
are available. 

b. Names that are globally resolvable to routable addresses should be
used within applications whenever they are available. Names that are
resolvable only on the local link (such as through use of protocols such
as LLMNR) MUST NOT be used in off-link communication. This can be
prevented by using LLv4 addresses or names resolvable on the local link
when an LLv4 address is used as the source address in the packet. 

c. LLv4 addresses MUST NOT be configured in the DNS."

Erik Guttman
ZEROCONF WG chair