What is Microsoft Exchange Server?

Microsoft Exchange Server is one of the most widely-used corporate software packages in the world. Being one of the key products of Microsoft, this email system is very well supported and has matured over its 25 years of service into a very stable software suite.

Exchange Server is a communication platform that includes email, calendaring, contact, scheduling and collaboration facilities for businesses. The package even includes telephony and document sharing. It is written to run on Windows Server, which provides many of the underlying services needed by the software.

The Exchange Server software is easy to install. However, a lot of different service options have evolved over the years, which means it may take some time for you to explore all of its screens and get it customized to run properly on your site. In this guide, you will discover exactly what Exchange Server does, how you should set it up, and what service you should expect from it.

Managing Exchange Server

The three most important aspects of an Exchange Server implementation are:

  • Connectivity
  • Authentication
  • Security

The complexity involved in keeping track of these factors makes managing an implementation a full-time job. However, Microsoft makes these tasks a little easier, by producing services that are common to many of its applications. For example, Active Directory (AD) will control your network permission rights, but it will also serve Exchange Server. So, once you have mastered the skill sets needed for AD on your network, you already have the skill set needed to manage user authentication for Exchange Server.

It is better to deploy specialist monitoring tool in order to keep on top of all of the interdependencies of these Microsoft services that contribute towards a successful Exchange Server implementation.

We will cover tools for managing Exchange Server later in this guide, but first we will explain:

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OS: Windows Server

  • How Exchange Server works
  • How you can set it up so that you don’t have any connectivity issues
  • How to add users to the system
  • How to keep your implementation secure.

How does Exchange Server work?

The Exchange Server package functions as a postal service for your business. Each employee will access emails through a separate system, which is called a “client.” The user software sends all emails written in the client environment to the server.

Exchange Server forwards all emails to the rest of the world. Emails destined for other users within the same network don’t need to go out onto the internet, but are made available through the client programs of those users.

All incoming emails for the organization are received by Exchange Server. The server program does not send these emails on to their destinations. It is the responsibility of the email client to query the server for the presence of pending emails and fetch them in order to make them available to their designated users.  An email can be stored on the server permanently, or deleted once it has been accessed by the client.

Clustering servers

Your company’s email service is one of the main channels of communication with the outside world. You cannot afford for it to fail. It needs to be available constantly and you have to make sure that all emails held on the server do not get lost through hardware failure.

It is very common to run Exchange Server across more than one physical server. This is not just for capacity issues, but as a safety guard against failure and maintenance downtime. Running more than one server for your Exchange Server email service is called “clustering.” Each instance in the cluster is called a “node.”

A standard set up for Exchange Server uses at least two nodes. One of these will be active almost all the time and is called the “home server.” The second will just be for data backup and to be on-hand should the home server fail or be taken offline for maintenance. This configuration is called “active-passive mode.”

You might have heard of an “active-active mode” for Exchange Server. This configuration enables two servers to be live simultaneously. However, that configuration is very difficult to manage and so it hasn’t been available since Exchange Server 2007.

You can have up to eight nodes is an Exchange Server cluster. There are four failover services available with Exchange Server. The options available to you will depend on your version of the email server system. If you have Exchange Server 2007, you will also have installed Service Pack 1. In this case, you have three failover/replication options. These are:

  • Cluster Continuous Replication (CCR)
  • Single Copy Cluster (SCC)
  • Standby Continuous Replication (SCR).

As a general rule of thumb, if you are able to run your cluster nodes on separate sites for protection against environmental damage, then opt for SCR. If you have a simple, single site implementation, then SCC will be good enough.  If you are still running a version earlier than Exchange Server 2007, you only have SCC.

If you see an option for Local Continuous Replication (LCR) don’t choose it. This is just a backup service that copies files to attached storage; it isn’t a clustering configuration and it won’t give you failover.

On Exchange Server 2010, you have a cluster definition that is called a Database Availability Group (DAG). As far as clustering services are concerned, the DAG is state-of-the-art. It will replicate your mailbox databases and manage failover automatically.

Whichever version of Exchange Server you have, you don’t have to worry too much about creating the cluster because the installation wizard will walk you through the information steps and then perform all of the configuration work for you.

Clients for Exchange Server

The client and server software elements of a corporate email system are not sold as a single system. This configuration enables a degree of flexibility when choosing interface software to serve the users of the email system.

Over the years of its operation, the functionality of Exchange Server has expanded to enable interoperability with a wider range of clients. The original client communicating protocol of Exchange Server is called MAPI and it is still in the system. This enables you to use:

  • Microsoft Outlook on Windows
  • Evolution on Linux GNOME
  • Hiri on Windows, Linux, and Mac OS

Mac-based clients can communicate with Exchange Server through Exchange Web Services (EWS). This group of client options includes:

  • Microsoft Entourage
  • Microsoft Outlook for Mac
  • Apple Mail

An email protocol designed for mobile users, called Outlook Mobile Access, gives access to both mobile apps and web-based clients, including:

  • Outlook for iOS
  • Outlook for Android
  • Outlook.com

Microsoft has added support for the open email protocols POP3 and IMAP4 to Microsoft Exchange. This gives you many other options when shopping around for email clients, including the addition of open email protocols which has expanded the client options open to businesses that use Microsoft Exchange.

  • Mozilla Thunderbird
  • Lotus Notes
  • Mail.com

Server to server interoperability

You don’t need to worry about connectivity issues and compatibility when operating Exchange Server with regards to the outside world. The system uses the Simple Mail Transfer Protocol (SMTP) to communicate with the other email servers in the world. This is the universal email system and all email servers connected to the internet can communicate through its messaging standards.

Implementing Exchange Server

Exchange Server is only available for the Microsoft Server platform. Although that limits your choice of server operating system, this restriction does have advantages. Many of the tools needed to support Exchange Server are built into Windows Server, so installing the Exchange Server software is a very straightforward task.

If you buy the very latest version, which currently is Exchange Server 2019, your operating system options are restricted even further because this version of Exchange Server will only install on Windows Server 2019.

Setting up Exchange Server

Apart from the tasks of downloading the installation file and running it, you have a few things to sort out when you create an Exchange Server implementation. You must calculate how much disk space, disk speed, CPU speed, and CPU capacity you will need on the host.

Calculate mailbox database storage requirements

  • Record user information for your current email system, or list facts about the user community a fresh email server is expected to serve. Categorize the users by user type/role.
  • For each user type, calculate the required mailbox size by examining how many emails each user is likely to send and receive each day, what percentage of those emails is likely to be retained, the average retention time for each email, and the average size of all emails and retained emails.
  • List organizational factors: service level objectives, number of sites, number of mailbox database copies, and storage architecture.
  • Note capacity trend factors, such as medium-term plans of the business to increase or reduce staff levels, planned new products, forthcoming product promotions, or corporate associations that will create an increase in email traffic.
  • Planned changes to communication channels, for example, a switch to team collaboration software, such as Slack, or a policy to encourage more contact by video conferencing apps.
  • List all user types and create a total mailbox database requirement for each. Increase or decrease each user group capacity requirement according to planned staff level changes. Increase the total requirements by your detected trend factor. Decrease the result by a factor that accounts for alternative communication channels that might lessen the usage of email.
  • Decide on a mailbox quota for each user type. For example, you can give a larger mailbox to sales staff than to other employee types. The maximum size of each mailbox does not directly influence capacity planning, but it is a factor in some capacity calculations.
  • Set an undelete window. That is, the number of days that you will allow deleted emails to be restored.
  • Add on the Recoverable Items Folder Size, which should then be multiplied by the number of users in each user type group and then derive a total requirement. Calculate this figure per user type as number of emails per day times the average message size, multiplied by the undelete period in days. Adjust this figure for some technical issues, overhead increase for retention to about 1.2 percent of the total mailbox size and for calendar procedures add space requirements of three percent of the mailbox size when emails are stored for potential restoration. So, add on the mailbox quota size times the mailbox quota size times 0.042.
  • Add on 20 percent of the total capacity that you arrived at. This is necessary to account for message indexing.
  • Add on a spare capacity. This is in addition to the trend capacity requirement and can be seen as elbow room in case of periodic unexpected surges in demand. This is called the “estimated database whitespace per mailbox.” This should be equal to one day’s worth of capacity per user.

If you have multiple mailbox databases on one disk, you need to have some spare space for processing. Microsoft recommends that you add one to the number of databases that you want to house on the disk. So, if you want to fit two databases on your disk, divide the spare capacity by three.

Calculate log file capacity requirements

Exchange Server 2010 and Exchange Server 2013 both have the same log file size of 1 MB. The table below from Microsoft Technet will help you calculate your log file capacity requirements.

If your average user email works out to be 75 KB, then you don’t need to make any adjustments to the figures in this table. However, you will need to create your own table if your user community sends smaller or larger email amounts on average.

Larger emails require slightly less than an exactly proportional amount of log file space. For example, an average size of 150 KB, twice the size of the emails in the sample table, produces a log file space requirement that is increased by a factor of 1.9, not two.

Your own log file recovery procedures will need to be factored into your capacity requirements (i. e., the number of days that you want to keep files and the number of copies that your security process requires.)

Calculate processing speed (IOPS)

The speed of your Microsoft Exchange server is dictated by a factor called the Input/Output Operations per Second (IOPS). This is the rate at which your hard drive can deliver data to requesting apps and it is the bottleneck on the response times of any storage-dependent application, such as a mail server.

The table below will help you in this calculation. This comes from the same Microsoft Technet article that includes the log file capacity requirements table above. The replication and failover procedures of Exchange Server mean that it doesn’t matter whether the node is active of passive.

Multiply the IOPS per mailbox shown in the table above by the number of users in the database and then by the number of databases on the server to get the total IOPS speed requirement for your disk. There are other interface speed issues that can impact Exchange Server performance, but IOPS is by far the lagger in the pack. If your disk meets IOPS requirements, it will have sufficient storage bandwidth.

Processor capabilities

Once you have your storage requirements figured out, you can move on to thinking about CPU. CPU sizing for the mailbox role is done in terms of megacycles.

Your CPU requirements for Exchange Server are expressed in Megahertz (MHz). The rate at which the processor will run is dictated by a number of factors, but mainly its clock speed.

The table below is supplied by the same Microsoft Technet article that contained the other two tables in this guide.

Be careful of the use of the “active” and “passive” terms in this table. Don’t think that you can get away with those rates for a failover server. Those low numbers are for servers that are for data backup only.

Capacity planning shortcuts

If these calculations seem complicated, you can use the Exchange 2013 Server Role Requirements Calculator. Another useful tool that Microsoft supplies is Jetstress to validate that the storage requirements can be met, and that the interface for your disk is fast enough to meet requirements.

Troubleshooting connectivity

It shouldn’t need stating, however, the host on which you install the Exchange Server software should be connected to your network and have access to the internet. The software for Exchange Server downloads from the internet, so you should be pretty guaranteed that your internet connection is running correctly once you get the package on your host.

All of the big, frustrating connectivity issues that you could face relate to the interaction between your Exchange Server implementation and the email clients that your company uses. Your best source of guidance in this situation is Comparitech’s How to test Exchange connectivity article.

Microsoft Exchange Monitoring Tools

You need to monitor many aspects of your network infrastructure in order to ensure that Exchange Server is running smoothly. Your best option is to use an automated system that will track system statuses and not require you to notice when things go wrong. Here are a couple of the top tools to consider.

SolarWinds Exchange Monitoring Tools (FREE TRIAL)

The SolarWinds table of monitoring and management tools are built on a common platform, called Orion. This means that you will be able to employ many different monitoring systems in order to keep your Exchange Server implementation running smoothly. The main module of this suite that takes care of all applications, including Exchange Server, is the Server and Application Monitor.

Although SolarWinds produces a separate database monitoring tool, its Exchange mailbox database monitoring system is built into the Server and Application Monitor. This helps with capacity planning, so if you run out of space in your database it will keep an eye on other storage issues, such as I/O speeds. The health of the host that runs your Exchange Server will impact on your email system’s performance and the SolarWinds monitors a range of server performance indicators including CPU capacity and speed, and disk space availability.

A user mailbox monitor in this tool will help you head off problems with the accounts of individuals using the email system. This and all other status monitors include an alerting mechanism, so you get notified of threshold triggers and don’t have to search through the dashboard’s screens for warning signs.

Pros:

  • Offers “done for you” dashboards, monitors, and templates designed for your enviroment
  • Provides live monitoring through its agentless architecture
  • Supports auto-discovery that builds network topology maps and inventory lists in real-time based on devices that enter the network
  • Can map applications, networks, and infrastructure as well as highlight bottlenecks and dependencies
  • Uses drag and drop widgets to customize the look and feel of the dashboard

Cons:

  • SolarWinds SAM is a feature-rich enterprise tool that can take time to fully explore

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ManageEngine Exchange Reporter Plus (FREE TRIAL)

Exchange Reporter Plus is a tool produced by ManageEngine to specifically report on Exchange Server, Exchange Online, and Skype for Business. ManageEngine is a major rival to SolarWinds in the field of IT monitoring tools and produces other services that relate to Microsoft Exchange Server. This package provides more than 450 report templates that can be run on demand or on a schedule.

The reports offered by this package examine mailboxes and server resources in general. You can request a report on features of the Exchange services, such as ActiveSync or the Outlook Web Access system.

There are three editions to this package. The highest plan is called Professional and it adds auditing and monitoring services to the reporting tool that is offered in the Standard edition. There is also an option that is free forever. The Free edition is the same as the Standard package but it is limited to reporting on 25 Exchange mailboxes.

You can get a 30-day free trial of the Professional edition. If you choose not to buy at the end of the trial period, your implementation of Exchange Reporter Plus switches over to the Free edition. The software package installs on Windows Server or you can add it as a service on your Azure account.

  • Offers on-premise and cloud deployment options, giving companies more choices for install

  • Can highlight interdependencies between applications to map out how performance issues can impact businesses operations

  • Offers log monitoring to track metrics like memory usage, disk IO, and cache status, providing a holistic view into your database health

  • Can automatically detect databases, server hardware, and devices for real-time asset management

  • Can take time to fully explore all features and options available

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Keep on top of Exchange Server

The implementation section of this guide just covered the more complicated and essential planning issues of running an Exchange Server. If you want to maintain this email system, you really need to be prepared to recalculate these factors on any given day.

Tracking the changes in demand on your email server and the performance impairments that other resource status problems can create is a very difficult task. This is why we recommend that you deploy a comprehensive and reliable monitoring tool.