Is it possible to get a public IP address on a T-Mobile mobile phone? (Windows Mobile <=> Exchange sync)

Hi

I am working for a company with offices in UK and Norway. Here in Norway the
mobile phone provider has the possibility to give a mobile phone a public IP
address.

I wonder if this service is available for T-mobile customers.



The reason for having public IP address on the mobile is that I consider to
set up synchronization between our windows mobile phones and Exchange 2003
SP2.

The recommended solution is to set up an ISA server between the exchange
server and the firewall / the Internet.

If I have public IP addresses on the mobile phone I can use functionality in
my firewall and only allow my mobile phones to communicate with my exchange
server.



As I can see, it is then not necessary to use an ISA server between the
firewall/Internet and the Exchange server?



Am I missing something here or is my conclusion correct? Is it possible to
get public IP addresses for T-mobile mobiles or do I have to set up an ISA
server to get high enough security?



Any information will be highly appreciated.





Best regards
Harald
Norway

Harald wrote:
> If I have public IP addresses on the mobile phone I can use functionality in
> my firewall and only allow my mobile phones to communicate with my exchange
> server.
>
> As I can see, it is then not necessary to use an ISA server between the
> firewall/Internet and the Exchange server?
>
> Am I missing something here or is my conclusion correct? Is it possible to
> get public IP addresses for T-mobile mobiles or do I have to set up an ISA
> server to get high enough security?

Restricting the access based on IP is not a particularly secure method.

Having said that, why you'd want to use ISA server is beyond me. What's
wrong with just using the firewall you have?? What does it give you that
a proper firewall doesn't?

Or when you say "my firewall" do you mean that you have a NAT router
with some basic IP-based filtering capability?

Geoff

not@vailable.com declared for all the world to hear...
> Any information will be highly appreciated.

I dont have a public IP and I sync with my companys exchange server over
https.
--
Regards
Jon

"Geoff Winkless" <usenet-at-geoff-dot-dj@[127.0.0.1]> wrote in message
news:465efedf$0$310$4d4eb98e@read.news.uk.uu.net.. .
> Harald wrote:
>> If I have public IP addresses on the mobile phone I can use functionality
>> in my firewall and only allow my mobile phones to communicate with my
>> exchange server.
>>
>> As I can see, it is then not necessary to use an ISA server between the
>> firewall/Internet and the Exchange server?
>>
>> Am I missing something here or is my conclusion correct? Is it possible
>> to get public IP addresses for T-mobile mobiles or do I have to set up an
>> ISA server to get high enough security?
>
> Restricting the access based on IP is not a particularly secure method.


I know restricting based on IP is not a secure method - but it is much
better to only open for 20 IP addresses than let it be open for the whole
world. :-)


>
> Having said that, why you'd want to use ISA server is beyond me. What's
> wrong with just using the firewall you have?? What does it give you that a
> proper firewall doesn't?


The reason for having the ISA server is that this is what is recommended by
Microsoft. When I asked my IT partner if they can guarantee the security
without the ISA server they could not.

The firewall I am using is a SonicWall with Enhanced OS. I have tried to
find out what the ISA server add, but it has been impossible for me to
figure out. That is also the reason I actually don't want to buy one. If I
can have enough security based on what I already have in-house I don't want
to add more system to look after.


>
> Or when you say "my firewall" do you mean that you have a NAT router with
> some basic IP-based filtering capability?
>
> Geoff

Harald

Harald wrote:
> The firewall I am using is a SonicWall with Enhanced OS. I have tried
> to find out what the ISA server add, but it has been impossible for
> me to figure out.
>
> The reason for having the ISA server is that this is what is recommended by
> Microsoft.

Well of course it is. That's like buying some Kraft flour which comes
with a free recipe on the side and it says "200g Kraft margerine" or
something - they're not going to say "just buy any old margerine",
they're going to suggest their own product.

(No, I don't think Kraft sell flour, but you get the idea).

> When I asked my IT partner if they can guarantee the security
> without the ISA server they could not.

Then _they_ should be able to tell you what it is that the ISA server
adds that your existing firewall does not. If they cannot then you
should seriously consider whether their services are as valuable to you
as they like to think.

All IMO, of course.

Geoff