I think that an additional comment might be worth mentioning here. It has to
do with the syntax of user%domain.com. Keep in mind that the % sign is
listed as one of the host delimiters that IMail recognizes. If this was
eliminated then it would not translate it to [EMAIL PROTECTED] The only issue
here would be your Netscape messenger users will need to something other
than the % in their Virtual Host Login Setup like the # or the & and make
sure whichever you use is still a valid host delimiter.

Eric S
----- Original Message -----
From: "Smart Business Lists" <[EMAIL PROTECTED]>
To: "Sanford Whiteman" <[EMAIL PROTECTED]>
Sent: Friday, May 31, 2002 12:30 PM
Subject: Re: [IMail Forum] Open relay problem with Imail


> Sanford,
>
> Thursday, May 30, 2002 you wrote:
>
> SW> In  what  situations  would  relaying for the backup be a requirement?
>
>     That's easy enough.  The case where someone has 2 IMAIL servers, A
>     and B, and each on separate networks.  A is backup for B and B is
>     backup for A.
>
>     I did test this too and you have to put both machines's IP in each
>     other's ACL to make the backup work.
>
> I just tested this whole thing again, too, just to remind myself what
> happens.
>
>     I have a primary server A_domain and backup B_domain.
>     I send a message to b_domain with rcpt_to written as
>        "name%C_domain@A_domain".
>     B_domain accepts this message because it is a backup for A_domain.
>     B_domain sends the message on to A_domain.
>     A_domain then sends the message to "name" at C_domain.
>
>     That is in the case where B_domain is also in the ACL of A_domain.
>
> I have not tested Eric's solution of removing B_domain from the ACL of
> A_domain but I assume Eric has tested this and that he is correct.
>
> Regardless, there is something puzzling about the way in which IMAIL
> handles the percent-sign e-mail address.
>
> If you have an address like "account@A_domain" then a message to that
> address should be delivered to "account" on "A_domain".
>
> In the IMAIL case and where "account" has a percent sign in it the
> IMAIL backup server (B_domain in my example) is perfectly capable of
> parsing the address, determining the domain (A_domain), looking in the
> HOSTS file to find A_domain's IP address, and checking the ACL to see
> if relaying is allowed for A_domain.  So it seems to me that IMAIL
> really does know how to find the domain for this address.  It makes
> sense that the part of the address that is not the domain is the
> account name.
>
> B_domain cannot ascertain if "account" is a valid account on A_domain
> so B_domain simply sends on the message at the first opportunity.
>
> So in my opinion there is nothing wrong up to this point and certainly
> it is demonstrated that IMAIL can determine the domain of the address.
>
> But now A_domain server receives the message which is still addressed as
> "account@A_domain".  But "account" actually looks like this:
>
>     "account2%C_domain"
>
> What should happen it seems to me is that IMAIL should check to see if
> this entire account name exists for the A_domain and if it does it
> then should deliver the message. If the account name does not exist
> then it should bounce it.
>
> And this is what happens in the situation where you send the same
> message to the A_domain server directly and not from the backup mail
> server.
>
> But in the case where the message is sent from the backup mail server
> IMAIL treats the account name as a new message address. At least in
> the case where the backup mail server (B_domain) is authorized as a
> relaying address for the A_domain (or if no relaying restrictions
> exist) then IMAIL on A_domain will endeavor to deliver the message to
> "account2" at the C_domain.  qed.
>
> I'm surprised IMAIL handles the message differently where there is no
> ACL for the backup.
>
> Regardless the fact remains that IMAIL is handling the ACCOUNT part of
> the address differently when it is received from a backup mail server
> and when it has a percent sign in it.
>
> This seems incorrect to me and I personally would still classify it as
> a "bug" or at least a decidedly strange feature.
>
> It is an interesting issue at any rate.
>
> Terry
>
>
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>


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