Re: RFC 1918

[Michael Shields <shields () msrl com>]

In article <20000714194722.AD3EA35DC2 () smb research att com>,
"Steven M. Bellovin" <smb () research att com> wrote:
> No -- 1918 addresses would only break PMTU if folks did ingress or 
> egress filtering for 1918 addresses.

It is easy to argue that using interface 1918 addresses and PMTUD are
incompatible with connecting to the Internet, for PMTUD requires
sending an ICMP message with the source address of the interface,
and using 1918 space on the Internet is not allowed.

RFC 1918 section 3:
   "In order to use private address space, an enterprise needs to
    determine which hosts do not need to have network layer
    connectivity outside the enterprise in the foreseeable future and
    thus could be classified as private. Such hosts will use the
    private address space defined above.  [...]  However, they cannot
    have IP connectivity to any host outside of the enterprise."

   "Indirect references to such addresses should be contained within
    the enterprise. Prominent examples of such references are DNS
    Resource Records and other information referring to internal
    private addresses. In particular, Internet service providers
    should take measures to prevent such leakage."
-- 
Shields.