Subject: Re: CAP & Latency

From: [email-masked]
Date: Tue, 28 Dec 1999 13:13:28 -0500

One more thing I forgot to include yesterday...

>I think of this like EMAIL. I do not know your physical address.
>My real intranet address is droyer@<some hidden host>.software.com.
>Yet [email-masked] gets to me. Same issue.

Another way its is NOT like eMail is that in eMail routing, the only 
address that gets rewritten is the destination one (from 
[email-masked] to droyer@<hidden host>.software.com).  The 
_sending_ address is not rewritten en route.  You wont find any 
(non-hostile) SMTP mail systems that say "Hey, this is from bkahn@<another 
hidden host>.iris.com so lets readdress it for him as 
[email-masked]".   You may find this behaviour in an SMTP Gateway 
between SMTP and another mail environment but in that case they are more 
than likely going to be in the return path; unlike the scenario so far.

WRT the flow:
>                                 CUA-1
>                                  |
>                                 |
>                                CS-1
>                                 |
>                                 |
>                                Company-1 firewall (no CAP access from 
outside)
>                                 ^
>                                 |
>                                 v
>                                Company-2 firewall (no CAP access from 
outside)
>                                 |
>                                 |
>                                CUA-2

For the inter company email to work they MUST allow outside SMTP access. 
Since SMTP is fairly well defined there are fairly straightforward ways of 
sending email in and out w/o much risk of security breaches.  If C&S is to 
target the same penetration as email then CAP will need to be permitted in 
much the same way.  Otherwise the comparison to email in this scenario is 
meaningless.

One of our goals in designing CAP should be to make its adoption by 
companies an easy choice.  One way to do this is to make it something they 
can adopt w/o risking their intranet or their internal systems and data. 
But this digresses from the case at hand...

Bruce
===========================================================================
Bruce Kahn                                INet: [email-masked]
Iris Associates                          Phone: 978.392.5335
Westford, MA, USA 01886                    FAX: and nothing but the FAX...
Standard disclaimers apply, even where prohibited by law...

---

From: Paul Hill <[email-masked]>
Date: Tue, 28 Dec 1999 14:05:32 -0700

[email-masked] wrote:
> Another way its is NOT like eMail is that in eMail routing, the only address that gets > rewritten is the destination one (from [email-masked] to droyer@<hidden host>.software.com).  The _sending_ address is not rewritten en route.

Your scenerio suggests that Doug's gateway doesn't rewrite your from address on your incoming
message, but you overlook one possibility that does exist.  Doug's gateway might rewrite 
Doug's from in Doug's outgoing message so that the message appears to be
from [email-masked] when it is really from droyer@<hidden host>.software.com.
This contradicts the statement that only the destination is rewritten.

Existing examples of this include large corporations which service their internet
mail through a large gateway mail machine and don't want the outside world to
know the names of internal machines and consider it a service so that
others don't have to keep track if someone moves machines within a company.

They also can provide the mapping from "droyer" to the more readable "Doug.Royer"
on the outgoing address.

I'm not sure how this relates to an analogous feature in i-calendar, but I
I thought I mention the extended nature of possible rewrites that do exist.

-Paul

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