Server for corporate email: Exchange, Zimbra, proprietary SMTP

For corporate email, you can choose between ready-made solutions like Microsoft Exchange or Zimbra, and deploying your own open-source SMTP server (for example, based on Mailcow), for which email server hosting will provide the necessary performance and data control.

In a world where digital communication is the foundation of business, a reliable and secure mail server is not just a convenience, but a critically important infrastructure element. The choice of solution for a corporate email server affects not only the speed of information exchange, but also the level of confidentiality, data control, and overall company security. In this article, we will examine the key aspects of deploying your own mail server, compare popular solutions, and provide recommendations for selection and configuration.

Why do you need your own corporate email server and how is it better than cloud services?

Many companies rely on third-party cloud email services, such as Gmail Workspace or Microsoft 365. They offer ease of use and minimal administration costs. However, your own mail server on a VPS or dedicated server from Valebyte provides a number of advantages, especially for companies that value:

• Full data control: All email correspondence is stored on your server, not on third-party cloud platforms. This is critical for compliance with regulatory requirements (GDPR, HIPAA) and internal security policies.
• High degree of security: You manage all aspects of security yourself, including firewalls, antivirus and antispam solutions, updates, and access policies. This allows you to adapt protection to the specific threats of your business.
• Flexibility and customization: Your own server allows you to install any software, configure any integrations, and adapt functionality to unique business processes.
• Independence from the provider: You are not tied to the terms of use, pricing policy, or potential limitations of a cloud provider.
• Economy of scale: For large companies with hundreds or thousands of users, the long-term cost of owning your own mail server can be significantly lower than monthly payments for cloud services.

Comparison of popular solutions for a mail server: Exchange, Zimbra, Mailcow

Choosing software for email server hosting is a key step. Let's look at three popular options, each with its own features.

Microsoft Exchange Server: who is exchange server hosting suitable for?

Microsoft Exchange Server is the gold standard for large enterprises and organizations deeply integrated into the Microsoft ecosystem. It offers not only email but also a full suite of collaboration tools: calendars, contacts, tasks, public folders, as well as seamless integration with Outlook and Active Directory. If your infrastructure is built on Microsoft products, then exchange server hosting will be a logical choice.

• Advantages: Deep integration with Windows Server, Active Directory, Outlook; rich collaboration functionality; high scalability and reliability; developed ecosystem of solutions and support.
• Disadvantages: High license costs (Windows Server + Exchange Server CALs); demanding on resources; complexity of setup and administration; platform lock-in to Windows.
• Server requirements: Minimum 16 GB RAM, 4 vCPU, 200 GB NVMe SSD for a small installation (up to 50 users). Large installations require dedicated servers with powerful processors, 32 GB RAM or more, and RAID10 SSD/NVMe.

Zimbra Collaboration: capabilities and advantages of Zimbra dedicated

Zimbra Collaboration is a powerful and feature-rich open-source solution (a commercial version with extended capabilities is also available) often considered an alternative to Exchange. Zimbra provides not only a mail server but also a full-fledged collaboration platform with a web client, calendars, contacts, tasks, cloud file storage, and chat. Deploying Zimbra dedicated on a Valebyte dedicated server allows for high performance and full control.

• Advantages: Open-source (Community Edition); rich collaboration functionality; user-friendly web interface; support for various protocols (POP3, IMAP, CalDAV, CardDAV); flexibility and extensibility.
• Disadvantages: High resource requirements (though lower than Exchange); complexity of setup for inexperienced administrators; commercial features (like Outlook Connector) are only available in the paid version.
• Server requirements: For 50-100 users, a VPS with 8-16 GB RAM, 4 vCPU, 200-400 GB NVMe SSD will be needed. For larger installations, it is recommended to use a dedicated server with 16-32 GB RAM, 6-8+ CPU cores, and fast SSDs.

Mailcow: open-source and flexibility

Mailcow is a modern, modular mail server solution based on Docker. It combines Postfix, Dovecot, SOGo (a web interface for email, calendars, and contacts), SpamAssassin, ClamAV, and other components, providing a ready-to-use, easily deployable, and manageable mail server. Mailcow is ideal for SMBs and developers who need high functionality with relatively simple setup.

• Advantages: Easy deployment thanks to Docker; all components "out of the box" (antispam, antivirus, web client); active community; high security; modern administrator web interface.
• Disadvantages: Requires understanding of Docker; collaboration functionality is less developed than Zimbra/Exchange (although SOGo provides calendars and contacts); relatively new project.
• Server requirements: For 10-50 users, a VPS with 4-8 GB RAM, 2-4 vCPU, 100-200 GB NVMe SSD is sufficient.

Other solutions: Postfix/Dovecot, iRedMail

For experienced system administrators who need maximum control and a minimal set of features, it is possible to assemble a mail server from individual components: Postfix (MTA), Dovecot (IMAP/POP3), SpamAssassin, ClamAV, Roundcube/Rainloop (web client). This requires deep knowledge but allows for the creation of a highly optimized solution. iRedMail is a script that automates the installation of such a stack, significantly simplifying the process.

Table: Comparison of Corporate Mail Server Solutions

Technical requirements for email server hosting: VPS or dedicated server?

The choice of suitable hosting for your mail server depends on the size of your company, the number of users, and the expected load. Valebyte offers both VPS and dedicated servers capable of meeting any requirements.

• For small businesses (up to 50 users) and startups:

  A powerful VPS is usually sufficient. Recommended configuration:

  • CPU: 2-4 vCPU (e.g., Intel Xeon E3/E5 or AMD EPYC).
  • RAM: 4-8 GB. Mail servers actively use RAM for caching and request processing.
  • Disk: 100-200 GB NVMe SSD. Disk subsystem speed is critical for working with mail databases. NVMe significantly outperforms SATA SSD.
  • Network: 1 Gbps port.
  • OS: Ubuntu Server, Debian, or CentOS.

  Such a VPS at Valebyte will cost approximately $20-50 per month.

• For medium and large businesses (50-500+ users):

  To ensure stability, high performance, and scalability, a dedicated server is necessary. Recommended configuration:

  • CPU: 4-8+ physical cores (e.g., Intel Xeon E3/E5/Scalable, AMD EPYC).
  • RAM: 16-64 GB.
  • Disk: 400 GB - 2 TB NVMe SSD (preferably in RAID1 for reliability) or fast RAID10 SSD.
  • Network: 1-10 Gbps port.
  • OS: Windows Server (for Exchange) or Linux (for Zimbra, Mailcow).

  The cost of a dedicated server at Valebyte starts from $70-150 per month, depending on the configuration.

It is also important to provide the server with a stable, "clean" IP address that is not on blacklists. Valebyte provides IP addresses with a good reputation.

Ensuring email deliverability and DNS records

One of the main challenges when deploying your own email server hosting is ensuring email deliverability. To prevent your emails from landing in spam, you need to correctly configure DNS records and monitor the IP address reputation.

SPF, DKIM, DMARC: configuration for high reputation

These three records are fundamental for email authentication:

1. SPF (Sender Policy Framework): Specifies which IP addresses are authorized to send mail on behalf of your domain. This is a TXT record in DNS.
2. DKIM (DomainKeys Identified Mail): Adds a digital signature to outgoing emails, confirming that the email has not been altered during transit and was indeed sent from your domain. This is also a TXT record.
3. DMARC (Domain-based Message Authentication, Reporting & Conformance): Combines SPF and DKIM, allowing domain owners to specify how to handle emails that fail authentication and receive reports on these checks. This is a TXT record.

Example DNS records:

; SPF record
yourdomain.com.   IN TXT   "v=spf1 mx a ip4:YOUR_SERVER_IP -all"

; DKIM record (selector is usually 'default' or 'mail')
default._domainkey.yourdomain.com. IN TXT "v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA..."

; DMARC record
_dmarc.yourdomain.com. IN TXT "v=DMARC1; p=quarantine; rua=mailto:[email protected]; ruf=mailto:[email protected]; adkim=s; aspf=s; pct=100; fo=1"

Replace YOUR_SERVER_IP and yourdomain.com with your own data. The public DKIM key is generated by the mail server (e.g., Mailcow does this automatically).

Reverse DNS record (PTR)

A PTR record (Reverse DNS) links an IP address to a domain name. Many recipient mail servers check for the presence and correspondence of a PTR record. If your server's IP address does not have a correct PTR record pointing to your mail domain, your emails are highly likely to be rejected or marked as spam. Valebyte allows you to easily configure a PTR record for your server through the control panel.

How much does a mail server cost: own server vs Gmail Workspace?

Let's compare the estimated costs of your own mail server versus a popular cloud service like Gmail Workspace (Google Workspace).

Gmail Workspace (Business Standard):

• Cost: ~$12/user/month.
• For 50 users: $12 * 50 = $600/month.
• For 100 users: $12 * 100 = $1200/month.

This includes hosting, software, support, 2 TB of cloud storage per user, and other Google services.

Own mail server (e.g., Mailcow on VPS/dedicated server):

• Hosting:
  • For 50 users (VPS): $30-50/month (e.g., 8 GB RAM, 4 vCPU, 200 GB NVMe).
  • For 100 users (Dedicated server): $70-100/month (e.g., 16 GB RAM, 6 CPU cores, 500 GB NVMe).
• Software Licenses:
  • Mailcow/Zimbra CE: $0.
  • Zimbra NE: From $1000/year for 100 users (can be more expensive).
  • Microsoft Exchange: Windows Server and Exchange Server licenses, plus CALs (Client Access Licenses). Initial cost can be several thousand dollars, plus annual support.
• Administration:
  • System administrator salary (or outsource): from $500/month (depends on workload and qualifications). Setting up and maintaining your own server requires time and expertise.
  • Additional services: Monitoring, backup, CDN for static files (if needed).

Estimated monthly costs (hosting + software only, excluding admin salary):

• Mailcow on VPS (50 users): $30-50/month.
• Mailcow on dedicated server (100 users): $70-100/month.
• Zimbra CE on dedicated server (100 users): $70-100/month.

As you can see, for a small number of users (up to 20-30), cloud solutions might be cheaper due to the absence of administration costs. However, when scaling to 50+ users and with an in-house IT specialist or the option to outsource, your own email server hosting becomes significantly more cost-effective, especially considering full control and customization.

Practical recommendations for selection and setup

1. Define your needs: How many users? Do you need calendars, contacts, chat? How important is full data control? What is the budget for software and administration?
2. Assess team competencies: Do you have an experienced system administrator capable of setting up and maintaining a mail server? If not, consider options with the simplest installation (Mailcow) or hire a specialist.
3. Choose reliable hosting: Prefer providers offering stable IP addresses, high availability, and quality support, like Valebyte. Make sure you can configure PTR records.
4. Configure DNS records correctly: SPF, DKIM, DMARC, and PTR are not options, but mandatory elements for successful email deliverability. Use online tools to check them.
5. Ensure security: Regularly update software, use strong passwords, configure firewalls, antispam, and antivirus. Log monitoring will help promptly identify and eliminate threats.
6. Plan for backups: Automatic and regular backup of all mail data and configurations is your insurance against information loss.
7. Monitoring and logging: Set up monitoring for server status and mail queues. Log analysis will help identify deliverability and security issues.

Conclusion

The choice between a cloud service and your own email server hosting depends on your business priorities. If you need full data control, a high degree of customization, and long-term savings when scaling, then your own mail server based on Exchange, Zimbra, or Mailcow will be the optimal solution. Valebyte provides reliable infrastructure in the form of powerful dedicated servers and VPS, which will serve as a solid foundation for your corporate mail server.