Do you need a CAS Server in Order to Use OWA in Exchange 2010 (E14)?

Not open for further replies.


We currently utilize Exchange 2003 Standard, and have OWA services. We do not have a CAS Server; therefore weren't sure if the same could be accomplished with Exchange 2010 Standard without a CAS Server.

Chris Morgan -

you can install the CAS, HUB, and MBX role (all required) on the same box, but yes it's required.Chris Morgan


to put it even more bluntly, a cas server is required for exchange 2010 PERIOD, even if you arent doing owa hehe


Well we are using a single box, and all we need is to manage a handful of mailboxes with OWA access.

So we DO have to install a CAS Server? Do you recommend a VM?


you just need the role itself, it doesnt have to be a seperate server if you arent concerned about high availability (i.e. setting up a DAG and cas array), you just need to have the cas role installed on your exchange 2010 server. As Chris said put the cas, hub, and mbx role all on one server to "mimic" the older methodology of exchange 2003

Chris Morgan -

Just in HAVE to install the CAS. Unless you understand the requirements and considerations for putting Exchange in a VM (it's not a small list) I would not recommend it. Virtualization can definitly benefit a smaller company, considering the budgets usually dont allow for amount resources needs to split out services and provide a proper infrastructure. But the impact of a poorly configured (taking all the defaults and just dropping VM's on a large pool of disks) virtualized environmnet can be ugly for an organization. Not trying to discourage it, just tossing out the cautions.Chris Morgan


There is one consideration. I have to check if there is the same problem with OWA proxy-ing as with Exchange 2007, when Mailbox role and CAS roll is install on the same Server. But in Exchange 2007 if both roles are install on server, CAS cannot proxy request for mailboxes located on Exchange server 2003.

Chris Morgan -

that problem doesnt exist with 2010. You have to use the legacy exchange url for that. And with the number of users they are talking about I would recommend dealing with coexistence. should be easy enough to just cut it all over at once.Chris Morgan


I appreciate that info. We will be migrating (transitioning) from Exchange 03 Standard to 2010 Standard within the next couple of weeks.

We do have the basic documentation on trasitioning from 03-10; however it doesn't say anywhere on the doc that the CAS and Hub have to be on it's own dedicated Server. Have any of you performed this type of maintenance, and if so; would you be able to answer the following:

1. What type of maintenance window (downtime) will we need to perform the switchover?

2. Any known issues w/ mailbox migration?


Sembee [MVP]

You do not have to have the roles on separate machines. In a small environment placing everything on the same box is fine.
Just to clarify the points above about OWA - Exchange 2010 doesn't proxy OWA for any older versions period. All it does is redirect. Therefore the issues of proxying from older versions of Exchange don't occur. If your mailbox is on another version and you login to Exchange 2010, then you will be redirected to the legacy URL.

There is no need for any downtime at all. Simply move the mailboxes when the users aren't around. Leave both the old and the new server active for a week or so, then remove Exchange 2003 correctly. Outlook will redirect to Exchange 2010 automatically.

Mailbox migration using the wizard is usually straight forward. Biggest issue is corrupt items, but you can't do much about that until it happens.


Simon Butler, Exchange MVP
Blog | Exchange Resources
Not open for further replies.
Similar threads
Thread starter Title Forum Replies Date
J Moved many emails to Outlook external folder, need to delete on Gmail server Using Outlook 14
A Wishlist Arthur workman I need the community's assistance thank you Using Outlook 3
A from Arthur to anyone I need your expertise assistance Using accounts in Outlook 7
Marc2019 Need help please! Cannot Setup my outlook email account on my Mac Outlook 2011 Using accounts in Outlook 2
T Need to backup to cloud storage, without desktop software - Testing UpSafe. Are there any similar services? Using accounts in Outlook 8
C need help setting up outlook first time Using Outlook 1
N Need help syncing contacts to iPhone X Using Outlook 8
L Need to import multiple Outlook files to Office 365 Account Using Outlook 4
S Received mail as part of DL, need to auto-CC the same when replying Outlook VBA and Custom Forms 5
C Need VBA code to automatically save message outside outlook and add date Outlook VBA and Custom Forms 1
S Error using AddressEntry.GetContact - need help Outlook VBA and Custom Forms 2
EaglePI Outlook 2010 need help with rules Using Outlook 0
Horsepower Need iCloud mail only Using Outlook 1
O Don't need any add-ins at all? Using Outlook 2
B Need Help - Willing to pay Outlook VBA and Custom Forms 10
A Need to view Outlook calendar in Sharepoint .. Using Outlook 2
J Need Help with Contacts VBA Outlook VBA and Custom Forms 1
L Accidentally merged a calendar with .ics, need to undo! Using Outlook 1
H Need help setting up GetFolderPath-Makro with Vodafone IMAP Mail-Account Outlook VBA and Custom Forms 0
D Need Genuine Office or Outlook 2007 Using Outlook 3
G how to cancel a recurring meeting but not the organizer but all attendees need to know. Using Outlook 1
H I need a developer to customize an Outlook Contact form Outlook VBA and Custom Forms 0
T Need help with finding/updating task Outlook VBA and Custom Forms 1
N Need a case sensitive rule Outlook VBA and Custom Forms 1
C Need rule to alert when an email has not been replied to within 24 hours Using Outlook 1
P Outlook 2003 - Do I need a new profile? Using Outlook 2
F Outbox - Multiple Emails need to be manually opened? Using Outlook 5
Miquela I need to make a calendar to share here at work with 40 other people Using Outlook 1
S Need CC: to show the original To: recip[ients Using Outlook 4
Denis Hi everyone!!! Need some help with Excel to Exchange Calendar??PLEASE>>> Using Outlook 1
D Need to extract a line from a word attachment, and add it to the subject line Outlook VBA and Custom Forms 3
Mary B VBscript: Need to copy every email to a folder & mark that copy as read Outlook VBA and Custom Forms 5
mikecox Desperat; need hands on support Using Outlook 1
E Need Help on Setting up a repeated Reminder on Task with Reoccurence Every Year Using Outlook 6
Glyn Do I Need Using Outlook 1
B Need Help Creating Email Based on Subject w Address in Body Outlook VBA and Custom Forms 1
G Need help configuring a PRF for Outlook 2010 and 2013 Using Outlook 0
K Excel Import Option: Need Help Updating Existing Records BCM (Business Contact Manager) 0
K Need help concerning emails linking to BCM. BCM (Business Contact Manager) 0
Stig Arvidsson Need a Script for handling moved mail from inbox Using Outlook 3
C Outlook 2010, Need to restrict domain users from installing any sort of a addin in outlook Using Outlook 2
J Need help with installation of BCM in Outlook2013 BCM (Business Contact Manager) 5
F Outlook 2010 - Need help with a custom field. Using Outlook 3
icacream I just need to copy my address book to my new laptop ! Using Outlook 18
D Need Help with Script. Keep getting Runtime Error 438 BCM (Business Contact Manager) 4
R Need help getting BCM to work with my Outlook 2014 Using Outlook 4
V Need to add some text in subject while creating new mails - NEED VB CODINGS Using Outlook 4
E Need a bit of education on how Outlook works please Using Outlook 3
G Outlook 2003 I need to move email to folder based on subject, using wild card Using Outlook 0
C In need of VBA code to read / parse HTML - Outlook emails Using Outlook 0

Similar threads