Archived from groups: microsoft.public.win2000.dns,microsoft.public.exchange.design (
More info?)
A smarthost is a mail routing host that is smart enough to know mail stores
and routes and can match up mail with the stores via the appropriate route.
It's often deployed in situations very similar to this one where I need to
accept mail for one domain and properly rewrite the destination and send it
along the most appropriate route to it's final mail store.
Using DNS records would be cumbersome and is not often used. Not sure how
many mailers would even look at those records to be honest and it would
likely break up some of the efficiencies of the sending host.
Downside to smarthosts are that you have extra hops in the path and extra
hardware as well as some sort of method to update those smarthosts.
FWIW, your wan link doesn't need to be taken up with email. You could route
all of your email via Internet if you wanted. Might make a smart host
uneccessary as well, but you'd have to check into that and decide. I'd
likely want to use some sort of transport encryption if I went that route
(TLS?)
Just a thought,
Al
"chriske911" <chriske911@yaghoo.com> wrote in message
news:mn.7a2c7d55f6b06dd3.32006@yaghoo.com...
> Al Mulnick wrote on 13/05/2005 :
>> Yes, there is another way called a smart host.
>> However, that may not meet all of your needs. Consider a company such
>> as, oh, Microsoft. They have one domain name microsoft.com. Several
>> equally costed MX records.
>> microsoft.com MX preference = 10, mail exchanger = mailb.microsoft.com
>> microsoft.com MX preference = 10, mail exchanger = mailc.microsoft.com
>> microsoft.com MX preference = 10, mail exchanger = maila.microsoft.com
>>
>> Do all of those have to be in the same location? Or country? Or
>> continent? Nope. But, and this is a big consideration, once one of those
>> mailers has the message, it must be able to 'deliver or die'. What I
>> mean by that is that if it accepts the message, by SMTP rules it now must
>> deliver it to the next host. That next host could be local
>> (geographically speaking) or it could be around the world. The next host
>> could be another SMTP mailer or it could be the users mail store.
>>
>> I'm going to make an assumption that once on your network, you don't want
>> to burn up the WAN link between Europe and America.
>>
>> So to make this work the way you are describing, I would personally
>> prefer a smart host vs. an Exchange server, deployed in Europe and
>> America. Both smarthosts would know the location and have routes to the
>> final destination servers. That route could be a subdomain (that you
>> register with external DNS. I.E. us.company.com and
>> europeancountry.company.com). To make this work, the smarthost would
>> have to know the information required for routing. If it gets a piece of
>> mail for US_User@company.com it would look that up in it's directory,
>> rewrite the delivery address, and then deliver it to the appropriate
>> mailer via the internet. That would look like
>> US_user@company.com -->change to US_user@us.company.com and then send it
>> to the appropriate mailer.
>>
>> That's valid if you don't want the traffic to route over your wan keeping
>> in mind that all users send as user@company.com regardless of location.
>>
>> Using DNS alone wouldn't do this because DNS doesn't have enough
>> information to route your mail appropriately.
>>
>> If you need more details, feel free to contact offline.
>>
>> Al
>>
>> "chriske911" <chriske911@yaghoo.com> wrote in message
>> news:mn.6c6f7d55c47823d0.32006@yaghoo.com...
>>>I have a problem where I have 2 sites on both european and american
>>>continent
>>> each site has an exchange server
>>>
>>> offcourse being just one AD domain there is always one mail server
>>> possible as highest priority mx record
>>>
>>> creating subdomains would be the answer for both sites to have a default
>>> high priority XC server
>>>
>>> management doesn't want a subdomain suffix in the email adresses
>>>
>>> is there a way to redirect mailboxes to the correct subdomain with the
>>> help of DNS records?
>>>
>>> or anther way that customers only need to use someone@company.com
>>> instead of someone@eu.company.com?
>>>
>>> thnx
>>>
>>> -- just a suggestion:
>>> http://home.in.tum.de/~jain/software/oe-quotefix/
>>>
>>> d;-p
>>>
>
> that's what I came up with too
> a sort of mail front server for routing to the correct back end servers
> hosting just one of those at an ISP somewhere in te world would do it for
> us
> there are only about 250 employees worldwide
>
> but I thought of a kind of redirection using DNS mailbox records or
> something like that
> off course it would make things more complicated
> since every change would have to be followed by a manual or half automatic
> DNS update
>
> but indeed, the external mail routing is taking up a lot of bandwidth of
> our WAN link
> I don't really care if it's internal mail cause that's the way it has to
> work
> but for mail coming from outside it could be avoided
> simply by implementing sub domains but that's not flying with management
>
> and offcourse they are right by saying it would complicate matters for our
> customers
> that's why the elaborate setup for something so simple
>
> what exactly do you mean by smart host?
> a mail server of any kind wich does relaying or something else entirely?
>
> thnx
>
> --
> just a suggestion:
> http://home.in.tum.de/~jain/software/oe-quotefix/
>
> d;-p
>
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