ietf-822
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Re: Mandatory From field, anonymity, and hacks

2004-07-31 13:58:47

On Thu, 29 Jul 2004 22:51:35 -0400, Bruce Lilly <blilly(_at_)erols(_dot_)com> 
wrote:


Charles Lindsey wrote:

Indeed, but "invalid DNS names" means, er, "invalid DNS names", and
"other  similar uses" should cover most other applications.

No. Printed examples place no load on DNS, testing has negligible
impact. Widespread use in messaging would place a large load on DNS.

I already explained that in reply to Keith. Naturally, agents that are minded to reply/followup to articles with .invalid TLDs in the from field need to check for the .invalid TLD. That should be obvious, and consequently the Usefor draft says 'Followup agents SHOULD NOT attempt to send email to any address ending in ".invalid"'.

And if you read further down in RFC 2606 (I don't have the exact words
in  front of me), you will see that it is recommended for use

I do have the text, and there is no such "recommend[ation]".

It says

      ".invalid" is intended for use in online construction of domain
      names that are sure to be invalid and which it is obvious at a
      glance are invalid.

which is pretty much what I said (and you snipped), and is exactly the intent of what is currently proposed in the Usefor draft.

Well, I might be inclined to prefer using a fixed, guaranteed black-hole
valid address if somebody wants to set one up...


It doesn't need setting up. The TLD ".invalid" already has the required
property

Wrong. There is a huge difference between NXDOMAIN and an MX record that
points to a server that discards messages.

No, I meant exactly what I said. If it is guaranteed, by IANA
registtration, that ".invalid" will never resolve, then agents need not
bother to try it.

You have missed the point.  Evidently you haven't looked at RFC
3696.

I have now looked at RFC 3696, and what Usefor proposes seems entirely consistent with same. Essentially, it says that if you intend user agents to check for and act upon particular TLDs, then you need to be pretty sure that your filtering is fully consistent with the relevant published specifications. A registration with IANA that a given TLD will _never_ resolve to anything seems as clear in that regard as one can get.


--
Charles H. Lindsey ---------At Home, doing my own thing------------------------ Tel: +44 161 436 6131 Fax: +44 161 436 6133 Web: http://www.cs.man.ac.uk/~chl Email: chl(_at_)clerew(_dot_)man(_dot_)ac(_dot_)uk Snail: 5 Clerewood Ave, CHEADLE, SK8 3JU, U.K. PGP: 2C15F1A9 Fingerprint: 73 6D C2 51 93 A0 01 E7 65 E8 64 7E 14 A4 AB A5