A single place to manage email, calendar, contacts, notes and tasks. In the office. On the road. At home.

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Kerio MailServer is a scalable messaging server that can support anywhere from 20 users, in a small local area network, to several thousands of users running from just one server.

Bottlenecks to scalability
Being designed for small and medium sized businesses, it is optimized to run on a single server. From the system standpoint, the scalability depends on the following:

• hardware parameters (memory size, hard disk speed)
• other server software running on the same computer

• number of concurrent connections to the Kerio MailServer
• content filter components used (anti-virus, anti-spam, attachment filter etc.)
• type of traffic (large attachments)

Estimating resources
On Apple PowerMac Dual 1.8GHz G5 with 512 MB RAM and 160 GB HDD, Kerio MailServer can process up to 500 concurrent IMAP users without a hit on performance.

On Apple Xserve Dual 2.0Ghz G5 with 512 MB RAM attached to an Apple Xserve RAID (RAID5), Kerio MailServer will handle the following traffic:

Components used	emails/sec	emails/hour
No anti-virus, no anti-spam	45	288,000
McAfee Antivirus, no anti-spam	35	126,000
McAfee Antivirus, SpamEliminator	8	28,800

Tested with a 7K email with no attachment.

User quotas
User quotas help administrators protect mail server resources with respect to hard disk space or RAID volumes in large scale deployments.

Advanced SMTP routing
Multi-branch corporations can use advanced SMTP routing so that each branch can enjoy the flexibility of managing Kerio MailServer locally.

Administrators can deploy two or more Kerio MailServer servers and have the primary mail server deliver email to local mail servers in branch offices. The branch office can then use its local Kerio MailServer to send email messages to local users, send them to other mail servers in the company network or domain, or directly to mail servers on the Internet.

Deploying local Kerio MailServer servers brings a few advantages over relying on just one central mail server. Most importantly, communication in a local area network is typically faster than over the Internet, therefore users will enjoy fast access to their mailbox allowing them to use Kerio WebMail for their daily work.