Re: Same Email Domain 2 Sites

Tech Tip: Click here to run a free scan for Windows Errors and optimize PC performance

in actual fact it is not the existing users who cause the problem here, it
is non-existant users.

ExchangeA has users A1, A2, etc... and is told to forward all mail for
unrecognised recipients to MailSystemB (ie. it does not have to be
Exchange).
Similarly, ExchangeB has users B1, B2, etc... and is told to forward all
mail for unrecognised recipients to MailSystemA.
What happens when someone sends mail to an email address that does not exist
on either server?

IMHO it actually becomes easier to handle by increasing the complexity, all
users are defined on MailSystemC (possibly hosted POP) and both ExchA and B
talk to it.

You can in fact get more 'SMTP' going with MailSystemC only acting as a
forwarding service.
MailSystemC has users@xxxxxxxxxx and knows to forward A1@xxxxxxxxxx to
A1@xxxxxxxxxxxxxxxx while also forwarding B1@xxxxxxxxxx to
B1@xxxxxxxxxxxxxxxxx

Though the 'primary' domain for the Exchanges at SiteA and SiteB are
'SiteX.domain.com' the recipient policy of each is adjusted so that users
get '@domain.com' addresses.

As you add sites the 'minimal' method gets even more complex, imagine four
(or ten) SBS's all forwarding in a circle, or worse, a mesh(HINT: DON'T go
there). Having the additional mail system ends up less complex and more
reliable.

I _once_ (or maybe twice) started thinking about how the 'additional' server
could actually be one, or all, of the involved SBSs. That _really_ gave me a
headache.

In reality, when the total user count exceeds SBS limit the best way is
non-SBS and if I was ever asked (again) to run multiple sites it would not
involve multiple SBS's. 'Sorry, too hard'.

"Joe" <joe@xxxxxxxxxxxxxx> wrote in message
news:eNA4emIrIHA.2256@xxxxxxxxxxxxxxxxxxxxxxx
Patrick wrote:
If I have to get the transition pack then I need to do that.

I don't want the same mailboxes on two machines, I just want the two
exchanges to route between eachother depositing mail in the correct
mailbox. I was hoping there would be a way to do that without needing to
get the transition pack.

So from what I understand, there's no way to get two exchange servers to
intelligently talk to eachother (IE route between one another) without
being on the same domain or having a domain trust setup between them?


It's routine for Exchange to share an email domain with an external
hosting company, and the KB article I quoted shows how to do that. That
doesn't depend on Exchange or trusts or Microsoft domains, it's
straightforward SMTP relaying. In the external host-SBS scenario, Exchange
neither knows nor cares which kind of mail server is the 'other' one. Most
ISPs' mail servers are not Exchange installations on Windows, and the
concept of Microsoft-type domains and trusts doesn't even exist for them.

While I haven't personally tried it, I would expect that two
shared-email-domain Exchange installations would correctly forward mail
for unknown recipients on the domain to each other. I would be confident
enough to invest a few hours trying it.


.