Exchange Installation
Exchange is the email server from Microsoft.
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Overview
In simple terms Microsoft Exchange [1] is a email and message platform for organizations. Exchange manages the mailbox database(s) and connects to Active Directory [2] for authentication and rights management.
Exchange can be hosted on-premise or in the cloud using Office365 [3] which Retain can also connect to.
Exchange has certain stated limitations [4], but even in cases where there are no stated limits, there are practical limitations you are going to reach.
“I usually recommend no more than about 2500 - 5000 messages in any of the critical path folders. The critical path folders are the Calendar, Contacts, Inbox, and Sent Item folder. Ideally, keep the Inbox, Contacts and Calendar to 1000 or less. Other folders, particularly custom folders created by the user, can handle having larger numbers of items without having a broad impact on the user experience (20,000 items in my "Cookie Recipes" folder? No problem - except when I need to find that recipe from last Christmas!).” [5]
Like many computer systems it works best when it is lightly loaded which in the case of Exchange means keeping as few messages the mailbox database as is practical and since the vast majority of messages are never viewed again after they are initially received it makes sense to get them out of the system.
The average user receives 120 emails a day, 260 days of the year or 31,200 messages a year.
Archive Strategies
Now it is certainly possible to have Exchange do its own archiving. You can set up a jounraling mailbox or hold to hang on to everything as certain laws demand. If you have to keep messages for 10 years and average user may end up have 312,000 messages consuming 20+ GB of storage. And that is just the average user, a power user would consume far more. Can you imagine the drag on your Exchange server trying to handle all of that?
You could create a policy to move messages into an archive database, but since it is still connected directly to Exchange it will still be a load on the system. However there are going to be "interactions" between the holds and policies moving things to the archive database that may not allow them to be successful.
This is where Retain comes in. Retain offloads all the messages so that Exchange can concentrate on delivering the messages rather then storing them.
The typical Retain setup does not do a true archive. The customer sets up a Retain server points it at the email server and has it do a dredge every night. For example, a message can come to a user, the user can read it, move it to the trash, and delete the trash. Has the message been removed from disk yet? No, it has not. It is moved to the Recoverable Items area of the database, where it resides for 14 days by default before being deleted. A user can undelete the message from Recoverable Items. However, they can also purge their Recoverable Items, which would remove them from the disk, not allowing Retain to dredge the message before it is deleted forever.
Unlike GroupWise, Exchange does not have message level retention abilities. So to make sure our customers are able to make proper archives there are some additional steps that need to be taken.
Microsoft recommends setting up a Journaling Mailbox if all messages are to be saved. There is a very large downside with this technique. If the Journaling Mailbox becomes too large, ~100GB (with various settings maximized) though it will be smaller in default systems, Exchange becomes unable to serve the messages so Retain can archive and delete them. This may work in small systems or in limited circumstances, but for the most part it is not the recommended technique for Retain.
- Exchange Journaling Mailbox Recommendations [6]
A more effective means of archiving messages in a large environment is to set up In-Place and Litigation Holds. These holds keep items from being removed from the Recoverable Items folder for a limited time.
- Exchange Archiving with In-Place Hold [7]
A hold will keep the message in the Recoverable Items folder until the hold is released.
A good strategy for archiving is to create a rolling in-place hold so Retain has a day or two to successfully archive the messages, since Exchange doesn't have a message level flag to specify if a message has been archived or not you want to leave a little extra time to make sure Retain has a fair chance to archive.
A better strategy is to maintain the hold for 14-90 days, which will provide plenty of time for discovery of errors and resolving them before data is potentially lost.
If users are going into Retain for past messages it is a good idea to have Retain wait to archive say 7-14 days so the messages are in their proper folders.
Required Exchange Server Roles
Exchange is one point in a cluster of servers for a functioning Microsoft network. [8]
There are only a few functions that are critical for our purposes:
- DNS (Domain Name Server)
- AD DS (Active Directory Directory Services)
- CAS (Client Access Server)
- Exchange Mailbox Server
In the lab these functions might all be on one server, in a large organization they would be spread across multiple servers.
DNS
The DNS server resolves the domain name and IP addresses within the network and all these functions need to point to the same one to work correctly.
If there are multiple DNS then they need to be configured with the correct information. [9]
One of the more common failure modes is that not all the servers are pointed to the same DNS.
AD DS
Active Directory Directory Services is how organizations organize domains, sites, computers, users and more. This is where the user Retain uses for access is created and resides. AD is where rights are assigned and maintained.
Retain logs into AD using SCP, EWS, autodiscover or LDAP.
One of the more common failures is that the Retain user's account has expired. How to check the status of the Exchange Impersonation User [10]
CAS
The Client Access Servers [11]
They are the front door of the network. They authenticate and route users to the correct database. When the Retain user logs into it is into the CAS, using Basic Authentication which needs to be enabled in IIS on the CAS server(s).
One of the most common failure modes is that Basic Authentication is not set up on the CAS for both EWS and autodiscover.
Exchange Mailbox Server
This is the server where the mailbox database we are accessing resides. As long as the Global Catalog User aka Retain Impersonation User has Application Impersonation rights to the directory it should be able to get to the data.
The main issue is setting policies for best performance:
- Retain and Exchange Server 2010 Throttling Policies [12]
- Large Attachments and/or Messages Cannot Be Archived [13]
Exchange for the Lab Environment
Installing Windows Server 2012 R2
Installing Exchange 2013 for Retain
Retain install
Retain Exchange Install Full install from scratch.
Retain Outlook Plugins
Retain Outlook Web Access 2013 Plugin these instructions actually work.
Retain Outlook 2013 Plugin Retain 3.4 and Outlook 2013 client.
