Exchange 2010 Hosting – Real World Consideration (Part 2)

If you would like to read the first part in this article series please go to Exchange 2010 Hosting – Real World Consideration (Part 1).


In the first part of this two part series we covered the following real world considerations in relation to hosted Exchange 2010 environments:



  • Data considerations from a legal perspective
  • An overview of cost to benefit ratios considerations
  • Whom owns the data
  • Support arrangements
  • Shared versus Dedicated Infrastructures
  • Considering the functional aspects that you require


In this part we will be covering considerations in regard to:



  • Considerations for resilient connections to a chosen provider
  • Migration –considerations for achieving your goals
  • Directory Synchronisation – do you don’t you?
  • AV & AS (Viral and SPAM)




The previous article of this series covered a number of “strategic” aspects to moving to a hosted Exchange 2010 arrangement with a cloud based service provider. In this part we will have a look at some of the more technical considerations that your business may wish to spend some time researching before choosing a vendor.


Considerations for resilient connections to a chosen provider


If you are looking to host your Exchange mail infrastructure outside your core network boundaries you will of course need a means to connect to it.


Your choices in regard to connectivity fall broadly into two main categories:



  1. Dedicated Leased line between your company and the hosting provider
  2. Connecting over the Internet to the hosting provider


There are of course pros and cons to both options – these are considered below.


Dedicated Leased Line





  • Generally considered more secure
  • Depending on the Service Provider can be considered more reliable than a standard internet pipe
  • Dedicated bandwidth for mail system traffic between your site and the vendors
  • Allows for closer inspection of traffic and a solid implementation of QOS should you wish





  • Is the more expensive option as you need to add the capital and revenue cost of the dedicated link to the project over a period of years
  • Some vendors do not support dedicated links into their infrastructures for hosted services
  • There is an argument that by adding in a dedicated link – you are technically not moving to a hosted service, but more of an Co-location arrangement where you are in essence just placing your mail environment within an extension of your network which you do not own
  • You will still require separate internet link to allow for OWA / Outlook Anywhere / Active Sync / BES services


Connecting over the internet to the hosting provider





  • Leverages pre-existing line provision therefore does not add additional cost
  • Easy to setup
  • True traditional hosting arrangement
  • Well supported by almost all vendors





  • Is considered less secure – therefore encryption of traffic between your site and the vendor is mandatory
  • Contention for bandwidth for the mail environment against that of the normal internet traffic which your firm generate – might put you in the position where an upgrade may need to be considered so that both services are maintained


Another primary consideration in terms of your network link is redundancy – if you have one of something (such as a communications link) and you lose it – then you would be disconnected from your mail environment. This would be the same in either case of a dedicated link or internet pipe – therefore as part of the project costs / risk analysis you will need to consider the option of dual pipes either via the web or direct to the supplier which can failover should the primary fail.




There are a number of things to consider about a migration to the new platform before you choose a vendor (or perhaps more to the point will need to discuss with any possible vendor before a contract is let) for example (and these are only a suggested few considerations):



  • How are you going to get your existing “on-premises” e-mail data from your local site to the cloud?
  • How are you going to manage the transition of your MX records for your domain to the hosting provider without mail being delivered to your old environment and the hosted environment
  • If you make use of a 3rd party archiving solution (such as Enterprise Vault) and you are moving the either Exchange 2010 compliance and archiving or the vendors offering – how are you going to get that information across and made available
  • How are you going to configure all of your existing Outlook MAPI profiles to use Outlook Anywhere?


So taking the above examples – many providers will take the view that the best way to get Mailbox data from point A to point B is via PST exports from your environment which are performed during a mutually agreed cut over period.


Transitioning your MX records from one supplier to another can be accomplished in a number of ways – for example a week before the agreed transition period lowering the TTL on the relevant records so that DNS replication takes place quicker; setting up your old environment to forward any incoming mail to a placeholder domain within the hosting environment– however this should be discussed in detail with any potential vendor.


If you currently make use of a 3rd party archiving and compliance product and wish to transition this to the cloud as well you will need to discuss with any potential vendor on how this would be accomplished, there is scope that existing archived mail could be exported to PST files and then importing into the cloud and indexed but this would need to be firmly put into the overall agreed scope of your contract.


Another point of consideration (especially in large environments) is how you will go about re-pointing all your Outlook clients (assuming that you wish to opt for full Outlook) from your in house Exchange installation to the hosting provider. Most hosting providers offer Outlook Anywhere – which of course requires a little more configuration within the MAPI profile to function – so you will have to decide:



  • If your user base is small do you manually repoint the clients?
  • If your user base is large do you attempt to script the changes?
  • If your user base is large do you purchase a MAPI management solution (additional project cost) to perform the job?
  • Do you get the hosting vendor to do it (additional cost)?
  • Do you just set people up with a new profile?


It pays to consider what you are going to do in terms of access before you let any contract as it will be a question that any good supplier will ask you.


Directory Synchronisation – do you don’t you?


In your current environment, users will typically logon in the mornings and open Outlook – all transparently where they only have to enter in their credentials once (at logon). Moving to a hosted environment you will want to maintain this status quo.


So how will it be achieved?


A number of hosting providers will suggest that they take a scheduled copy of your AD environment to a domain controller on their site which will allow for authentication to take place – but there are a number of alternative methods that you may wish to consider (federation for example) – all of which need to be discussed with or suggested by any potential vendor.


The key thing is that you consider this as a requirement and build it into any contractual agreement – or if this is not an issue for your company accept that people will have to log on twice and put this down as a method of increasing security.


AV & AS (Viral and SPAM)


Most (if not all) hosting providers will offer Anti-Viral and Spam stopping services as part of any hosting package. However if you are already signed up to a service within your current “local” Exchange environment (e.g. Message Labs, Web SaaS, Postini, etc.) and have contracts still to run with them – you may wish to consider the option of maintaining those agreements and redirecting them to the hosting provider.


Good hosting providers will not push their “in house” solutions on you, and will flex to your requirements and needs and will be benevolent towards you in maintain them until such time that you wish to move them over.


You should consider discussing this with any potential vendor that you evaluate and weigh up the “pros and cons” of maintaining existing contracts, against a full switch over.




In this second part we have covered some of the technical analysis that needs to be undertaken before moving to Exchange in the “Cloud” and hopefully given you a number of pointers which you can use in your own projects.



If you would like to read the first part in this article series please go to Exchange 2010 Hosting – Real World Consideration (Part 1).

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