Email Problem (plusnet people and clever people please!)

[#1]

I have a problem with email which is really bugging me.
If someone from the outside world emails myself and another employee we both get the email twice.
There is a pattern; if there are two employees on the To or CC line they both get the email twice, if there’s 4 employees all 4 people get the email 4 times, and so on.
If an email is sent internally to 3 employees they only get a copy of the email once.
What I think might be happening is this:
Bob sends an email to jeff and adam, both are on the 'To' line. Naturally he will send two emails (I think?), plsunet will collect both emails on the same account. Exchange will look at email 1 and say I recognise jeff and adam; heres your emails. It will then look at email 2 and say excatly the same, thus sending a number of emails depending on the number of recipitants?
I reluctant to think this is a problem with Exchagne as it does not repeat emails internally. Is this something that force9 might be able to help with?

[#2]

How is the mail being delivered to the Exchange server?
Is it being delivered to POP mailboxes at Plusnet's side, then Exchange is retrieving it from those?
If so, your supposition is probably correct. 
I suspect that Exchange is routing on the "To" address.  If this is the case there are a few things you can do to fix this problem:
1.  Make the Exchange POP Connector use the Envelope-To: header instead of the To: header.  This header will only appear once in each email, and will be the email address that the mail was delivered to.  Unfortunately, I'm not familiar with Exchange to be able to talk you through it - although if you let us know which version then someone may be able to talk you through.
2.  Arrange for your mail to be delivered to the Exchange server via SMTP.  This is not for the faint of heart, but it does mean that your mail will be totally controlled by the Exchange server, and Plusnet won't actually touch it at all. 
Option 2 means that your mail won't be 'Postinied' either so you should have some spam/virus control in-place on your Exchnage server.  You'll also need to look at dequeueing mail from Plusnet for times when your Internet connection is down.
B.

[#3]

yes it is pop.
If option one is possible, I will try and give this ago.
I ddefinatly want to go through postini since ive seen a massive improvement since being on the program.

[#4]

What version of Exchange are you using?  I'll see if I can dig out how to alter it.
B.

[#5]

exchange 2003.
Ive had a good look myself but doesnt appear to be alot 

[#6]

I believe the SMTP connector is enabled by default on exchange, you can test this:
Start > Run > type 'telnet' (no quotes) and hit enter
Type 'o <your exchange server address> 25' and hit return, if you see something similar to the following, you are ok;
"220 Domain-name.co.uk Microsoft ESMTP MAIL Service, Version: 6.0.3790.1830 ready at  Fri, 1 Feb 2008 08:59:23 +0000"
This means you have successfully connected to the SMTP server.
Can you give this a try, and let us know if the SMTP service is ok. I am finding my documents to disable pop3 collection now!

[#7]

220 mydomain.co.uk microsoft ESMTP Mail service, Version: 6.0.3790.3959 ready at <todays date/time>

[#8]

Just been having a read up on this, and it appears that Barry is right about the interpretation of the addresses.
It sounds to me like you use the 'catch all' mailbox, with Exchange collecting mail via POP3, and then dropping it into local mailboxes - does this sound right?
If so, the easiest way might be to create individual mailboxes via the link:managemail tool.
This should ensure that it works as expected.
You'd have to set up the POP3 collection for each new mailbox on your exchange server I believe too.

[#9]

I REALLY dont want to create 50 mailboxes because plusnet has changed the way its routed (since we've always used a catch all from day dot). The multiple email cases started just over a year ago. When I created a ticket F9 just shrugged their shoulders and told me to do the same.
I personally dont think its the correct way to do it in a business sense. What If we was a huge company with 100's of users?
Yes James, that does sound correct.

[#10]

Erm, without sounding confrontational, collecting your mail via POP3 is *not* the way to be doing it if you have so many mailboxes.
Is there a reason for not using SMTP?
Its far and away the most robust solution, and the expected configuration for using an Exchange Server.
If you have a real desire to use POP3, you really ought to have saved yourself the license fee, and not bothered with Exchange. Clients could simply download their own mail from F9 via POP3.
A simply change to your F9 config, a little tweak of your Exchange box, and you can take full control of your mail, and use Exchange as its intended.

[#11]

without postini?
Exchange came free with sbs 2003 so we never spent any more money.

[#12]

Yup, without Postini.
If you use SMTP delivery, your server creates a connection with the mailserver [specified by the MX DNS records] for the domain you are sending the mail to.
Your server then delivers the mail directly.
Other servers do exactly the same thing, so they would examine your domain MX record (thats the config change you'd have to make in the portal assuming you are using a PN hosted domain) to find out your IP address.
They then attempt to make an SMTP connection to that IP address, and they deliver your mail direct.
Kinda like ditching the Post Office and having people bring their letters direct to your door.

[#13]

We run Exchange 2000 in Pop3. I would love to switch to SMTP but I do like the idea of PN Virus scanning and Postini as 'outer perimeter' defences, we have software on the server as 'inner perimeter' security.
As Barry said, not for the faint hearted though.
Interestingly we had a reverse of Adam1V's issue.
If someone locally emailed accounts at head office and cc'd the MD at head office they both received two identical copies.
During a string of M$ updates the problem disappeared.

[#14]

Im with Strat, the amount of spam and the idea of implicating our own spam filter against setting up the SMTP just isnt worth the hasslie I think.
Our Server is quite up to date with hot fixes