What’s not available in Exchange 2010 SP1 Hosting Mode

This is what documented in the Exchange 2010 SP1 beta Hosting Deployment Help file,

Exchange 2010 SP1 doesn't support the following features in Hosting

  • Exchange Management Console
  • Public
  • Unified Messaging Server role
  • Federation
  • Business-to-Business features such as cross-premises message tracking and
    calendar sharing
  • IRM
  • Outlook 2003 support (EnableLegacyOutlook)
  • Edge Transport Server role


When I look at this and trying to think about what some of the current HMC hosters will think, I believe they will probably say, no big deal except for Public Folder and Outlook 2003 support. 50% and probably more of the HMC hosters that I came across provide Public Folder as part of the deal. Obviously, taking away Public Folder means that Outlook 2003 has to go too because you can't have Outlook 2003 without Public Folder, it just won't work. It also means, you have to provide some form of migration for your customers who currently has access to Public Folder to other solution such as SharePoint. That will definitely make things a little bit more complicated and require more advanced notice and planning. So, might be something to think about as you are doing your planning right now. At the same time, it may not be a bad idea to start planing to encourage your customers to upgrade to Outlook 2007 and above if they haven't done so. I know, I know, it is definitely easy to say than done.

Having to say that, in my humble opinion, Public Folder is definitely worth removing for a number of reasons even though I think some of you might disagree, 

  • Managing Public Folder quota is a big mess. The only way to manage the quota is to ensure that the public folder is created from a control panel and have the quota appropriately enforced. Too often, this is overlooked. I have met a lot of people who assumed that when you assign a quota of say 100MB to a folder, it will calculate 100MB of size for all the content as well as the content of the sub folders in that folder. Unfortunately, that's not true. Each folder has it's own quota limit and it doesn't inherit the quota from the parent folder. As a result, in order to have a good enforcement of size in public folder, you must not allow your users to create sub folders using Outlook because if you allow that, you will lose control. I have come across many customers who initially offered their customers a 100MB folder but end up hosting over 5GB of data just for that organization.
  • Public Folder OAB cannot scale well. Alright, here is a shameless cut and paste from Grahame, 'There is a known problem with Public Folder OABs. Each of these generates a Replid and we have seen that more than approximately 20 000 of these can lead to … A workaround has been developed which allows small organisations to share an OAB (users are not aware it is shared). See <> for details. Note that this limit applies only to PF-based OABs. Hosters expecting to have many thousand hosted organisations should deploy web-based OAB distribution in HMC 4.5.' You can find the the FAQ by Grahame Ash from here, http://blogs.msdn.com/b/mkostersitz/archive/2010/05/03/hmc-4-x-faq-by-grahame-ash-principal-premier-field-engineer.aspx
  • No last accessed date for Public Folder. There is no attribute in each of the item in the Public Folder to tell you when was this item last accessed. So, in another word, you don't really know any of those document is active. This is one big weakness of Public Folder. In addition, unlike in SharePoint, you can't have any versioning as well.

I can definitely name a few more but I will stop here. I think it is going to be a slightly painful process to move people away from Public Folder but I still think it is way worth it.

Comments (16)
  1. Anonymous says:

    Hi Matt,

    You are right. Older version of Entourage will fail. However it is not because of Public Folder but because WebDAV was dropped in Exchange 2010.

    One of the things you should take note though is that this is SP1 beta. Things may change in SP1 RTM or it may change in SP2 especially for future stuff like UM or OCS 2010….

  2. Anonymous says:

    @ Dermot. To some extend I agree with you on the Edge but having dealt with Edge Transport in HMC 4.0 before, it was actually quite a painful experience, I have my concerns too. That's why you find Edge Transport was not recommended in HMC 4.5. And yes, I do see the point for needs of recipient filtering. Recipient filtering is great but not without problem too. That's why when you have recipient filltering, you also need to make sure there is tarpitting to avoid directory harvesting and etc. It also means every RCPT TO will result in the system to make a query of the validity of the recipient and hence increasing time for each SMTP TCP connection which may adds up to quite a fair bit for  a hosters as you may potentially have a couple millions of users (like some of the hosters that I dealt with).

    Now, the HT itself can be enabled for antispaming features but I am not sure if the recipient filtering is working well in hosting mode. I haven't spent time to look into this but I do see points why we should do this and why we shouldn't do this.

    Now, if you have a non-MS SMTP relay box, there is also no stopping you from doing LDAP query to DC to find out the validity of the recipient before allowing the mail delivery.

  3. Anonymous says:

    @ Carlos. UM is not available yet as it wasn't in the scope of the SP1 Hosting Mode.

  4. Anonymous says:

    Hi Mobay,

    Do have a look at http://www.microsoft.com/…/splabenefits.aspx. You should get the necessary information from there.


  5. Anonymous says:

    I don't have a lot of information on LIve@edu that I can share. What I can tell you is that, yes, Microsoft developed Exchange 2010 as a service first, using it to power its Live@edu mail service and then worked to create the server version of the software– sort of a reversal of the past way Exchange and other products have been created. So, in other word, what you are seeing and will be seeing in the Hosting mode is very much derived from that.

  6. Anonymous says:

    Out of the box, there is nothing but it can definitely be done using other products like MIIS, FIM and etc. At the end, you want to sync a few things, password, creation/modifications/removal and etc.

  7. klil says:

    HI.. how actually to do a hosted exchange similar to outlook.com live@edu, does microsoft use exchange 2010 Sp1 hosting mode, or they have secret way on how to do it.

  8. Mobay says:

    Hello and thanks for sharing your information.

    I have a question. What requirements must be meet to be a exchange 2010 hoster. Can anyone buy the Exchange 2010 license for hosting mode? Or do you have to be Gold Partner or something else?

    Thanks in advance

  9. grahame says:

    To run Exchange 2010 in Multitenant/Hosted mode you will need either the SPLA or HVS licence.

  10. Mobay says:

    Thanks! So anyone can buy those licences? Heard a rumor that you might need a special relationship with Microsoft.

  11. Matt says:

    Since Public Folders and by proxy Outlook 2003 are not supported, I imagine this means only Entourage with EWS and Mac Mail using EWS will be supported on Exchange 2010 versus older versions of Entourage.

    I would be curious to see more information on the Federation portion not being supported.  I understand the Unified Messaging component as Microsoft is indicating that you cannot do multi-tenant UM with OCS 2010, at least that's what I'm hearing. 🙂


  12. Peter Stutzinger says:

    Hey there,

    is it possible that the mailbox import/export request has also been removed from hosting mode? i've tried to import a pst file, but the cmdlet is missing from all servers….

  13. Carlos Jesus says:

    Hey Kip, why Unified Messaging Server role not is available in Exchange 2010 SP1 Hosting Mode?

  14. Dermot Canniffe says:

    One of the major drawbacks I've seen with Hosted Exchange 2010 not supporting Edge Transport is that dynamic recipient verification is therefore not available for other appliances on the network. This is problematic if you have a separate unit relaying SMTP for example.

  15. New 2 This says:

    How do you Sync the Client/Customer AD with Hosted Exchange ?

  16. IanCurrie says:

    Hi Kip,

    Great series of articles, thanks.

    In non-hosted Exchange environments, we deploy Forefront TMG appliances (with Edge Transport/Forefront PfE integrated) to provide anti-SPAM at the edge.  How can we best workaround the lack of Edge Transport support in a hosted scenario (recipient filtering not essential)?  Aside from running Forefront PfE on the HT's, must we install a non-Microsoft anti-SPAM solution?  

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