ActiveSync + Multiple Front-End Exchange Servers

I am working at a client site and they are looking to use round-robin DNS to
allow Windows Mobile ActiveSync users to connect to multiple Front-End
Exchange servers using a single existing external DNS record. Is this
possible with ActiveSync? If so, has anyone seen any issues in the past
with Treo devices syncing to multiple servers with the same DNS name? Any
help that can be provided will be much appreciated. Thanks.

Hi,
ActiveSync is actually two things:

1. On the desktop, ActiveSync is the program users install to synchronize
data with Outlook.
2. In Exchange 2003 SP2 or 2007 Exchange ActiveSync is the over the air
synchronization solution Microsoft offers for Windows Mobile.

If you mean Exchange ActiveSync, there will be special requirements such as:
1. Having the same public digital certificate installed on both machines.
2. Having the ability to resolve and access the external host by the host
name.
3. Not changing the IP/host name during access. Basically the user will see
an error because the original host is not acessible. Keep in mind that
Exchange ActiveSync keeps the TCP HTTPS connection open with periodic (in
minutes) keepalives.

Also, you will see that the Windows Mobile device will only perform a DNS
lookup ONCE until a soft reset is performed or all networks are disabled.
This was done to reduce the latency for dns lookups on subsequent requests.
There is no option to require the system to perform DNS lookups more often.

I hope this helps.

Sincerely,

--
Chris De Herrera
http://www.pocketpcfaq.com
http://www.pocketpctalk.com
http://www.tabletpctalk.com
http://www.mobilitytalk.com

"Ern" <> wrote in message
news:36702B62-9833-4566-A8BB-...
>I am working at a client site and they are looking to use round-robin DNS
>to
> allow Windows Mobile ActiveSync users to connect to multiple Front-End
> Exchange servers using a single existing external DNS record. Is this
> possible with ActiveSync? If so, has anyone seen any issues in the past
> with Treo devices syncing to multiple servers with the same DNS name? Any
> help that can be provided will be much appreciated. Thanks.

The same public digital cert has been installed on both servers and the
external DNS record will be changed shortly to allow the record for
mail.xxx.com to reply with either server addresses in a round-robin fashion.
The ActiveSync DNS lookup info that you provide is very helpful. So as long
as both servers are up, that the mobile devices should be good since they
will not perform a new DNS lookup until they are reset, is this correct?


"Chris De Herrera" wrote:

> Hi,
> ActiveSync is actually two things:
>
> 1. On the desktop, ActiveSync is the program users install to synchronize
> data with Outlook.
> 2. In Exchange 2003 SP2 or 2007 Exchange ActiveSync is the over the air
> synchronization solution Microsoft offers for Windows Mobile.
>
> If you mean Exchange ActiveSync, there will be special requirements such as:
> 1. Having the same public digital certificate installed on both machines.
> 2. Having the ability to resolve and access the external host by the host
> name.
> 3. Not changing the IP/host name during access. Basically the user will see
> an error because the original host is not acessible. Keep in mind that
> Exchange ActiveSync keeps the TCP HTTPS connection open with periodic (in
> minutes) keepalives.
>
> Also, you will see that the Windows Mobile device will only perform a DNS
> lookup ONCE until a soft reset is performed or all networks are disabled.
> This was done to reduce the latency for dns lookups on subsequent requests.
> There is no option to require the system to perform DNS lookups more often.
>
> I hope this helps.
>
> Sincerely,
>
> --
> Chris De Herrera
> http://www.pocketpcfaq.com
> http://www.pocketpctalk.com
> http://www.tabletpctalk.com
> http://www.mobilitytalk.com
>
> "Ern" <> wrote in message
> news:36702B62-9833-4566-A8BB-...
> >I am working at a client site and they are looking to use round-robin DNS
> >to
> > allow Windows Mobile ActiveSync users to connect to multiple Front-End
> > Exchange servers using a single existing external DNS record. Is this
> > possible with ActiveSync? If so, has anyone seen any issues in the past
> > with Treo devices syncing to multiple servers with the same DNS name? Any
> > help that can be provided will be much appreciated. Thanks.
>
>