Comparison of Microsoft Exchange to Open Source Sendmail - Features, Interfaces, and Manageability

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Microsoft Exchange 2003 versus Open Source Competitor “Sendmail” - Comparison of Features and Benefits

Microsoft Exchange vs. Sendmail

Some Assumptions and Misconceptions

We assume Microsoft Exchange Server 2003, as Exchange 2007 is still being rolled out slowly in many companies; thus 2003 is the prevalent version at the moment.

We assume open source Sendmail (non-commercial and free). We also assume the given fact that the basic Sendmail product, without other added open source modules, does not have an OWA (Outlook Web Access) comparable web-based email interface offering. Also missing from the core Sendmail package is calendaring; therefore, without those equalizing factors, some comparisons may attempt to show Exchange as “more feature-rich” when, in fact, with the proper add-ons, Sendmail can be just as feature-rich.

Microsoft Exchange Offerings

Microsoft Exchange is an add-on product and is not included by default with Windows operating systems; thus, there is an added expense involved with obtaining and implementing Exchange.

Microsoft Exchange is managed via both its own Exchange management GUI interface as well as the fact that it integrates tightly and seamlessly with Microsoft’s Active Directory. Through Active Directory, many Exchange administrative features can be easily carried out; such as creating a user’s Exchange mailbox, setting a user’s mailbox size quota, and enabling/disabling access to the mailbox.

With Exchange 2003 and earlier, Microsoft’s email database used a more ‘closed’ and proprietary model. With Exchange 2007 and forward, the enterprise email database may now reside completely on an enterprise’s SQL server. Prior to Exchange 2007, only the logging database could be a SQL database.

Microsoft Exchange servers support POP, IMAP, MAPI and SMTP functionality.

Sendmail Offerings

Sendmail comes included free with most versions of Unix and Linux.

Sendmail is easily customizable, but is driven primarily from the command line.

Sendmail can provide enterprise-level ‘mail exchange’ functions; that is to say, it can function effectively as an enterprise’s email platform or as a gateway to other email platforms.

Web components, similar to Outlook Web Access, can be provided in conjunction with Sendmail via other open source products such as squirrelmail –

For Sendmail, the file is the primary Sendmail configuration file.

Even using commercial Unix or Linux offerings, some estimates show that, due to per-seat licensing costs of Microsoft Exchange, the costs can reach 100% higher than the equivalent cost to purchase, for example, a Sun Solaris-based system for hosting Sendmail with the Solaris Internet Mail Server (see the reference at the end of this article).

This CRN article points out that Exchange can cost about $70 per seat and that a comparable commercial Linux-based equivalent can cost $50 per seat. Alternatively, completely free open source offerings can be used, in which case the per-seat Unix/Linux cost would be significantly less, potentially $0.

Additionally, Sendmail offers some easily-customizable server-based spam filtering options, whereas Microsoft Exchange does not.

Various other open source add-ons can be implemented in conjunction with Sendmail. One such add-on is phpGroupWare, which provides calendaring and address book functionality.

Also note that some open source products provide a GUI-based management interface on top of Sendmail, thus making it easier to configure and maintain.

Sendmail supports POP , IMAP and SMTP functionality. Note: As a front-end Sendmail client, you may even utilize Windows-based Microsoft Outlook clients, as long as you configure Outlook properly to access your IMAP or POP Sendmail server.


Microsoft Exchange 2003 offers a robust, integrated and extensible enterprise email platform, but at what cost? If a company is firmly entrenched as a Microsoft shop, then they may be able to obtain the appropriate legacy price breaks needed to justify any added cost of licensing and maintaining Microsoft Exchange. At the same time, it is useful to note that there are free Open Source alternatives such as Sendmail that provide basic and extensible equivalent enterprise email functionality.


A “Microsoft Exchange versus Sendmail” article:

Sendmail may be obtained from:

Microsoft Exchange may be obtained from Microsoft and its resellers:

Evolution/Sendmail vs. Exchange/Outlook:,289625,sid39_gci1064729,00.html

Although rather inaccurate, the below link provides a line by line feature comparison. Note that some of the items not checked are rather inaccurate, since you can indeed have a web interface as well as a management GUI on the open source Sendmail server.