How can I hide my mail server IP address or mitigate attacks against it?
Summary
What email marketers say9Marketer opinions
Email marketer from Gmass Blog explains segmenting email lists and sending targeted emails. This helps to improve engagement rates and reduces the likelihood of recipients marking your emails as spam.
Email marketer from Neil Patel's Blog shares that to prevent email spam and protect your server, you need to implement SPF, DKIM, and DMARC records. These authentication methods verify that your emails are legitimate and prevent spoofing.
Email marketer from Digital Ocean Community explains that using a firewall to restrict access to your mail server is crucial. Only allow connections on the necessary ports (e.g., 25, 110, 143, 465, 587, 993, 995) from trusted sources.
Email marketer from Reddit suggests using a combination of rate limiting, greylisting, and content filtering to mitigate attacks. They emphasize that a multi-layered approach works best.
Email marketer from MXToolbox Blog explains that monitoring blacklists is essential to maintaining your server's reputation. If your IP address is blacklisted, your emails are more likely to be marked as spam.
Email marketer from SendPulse Blog shares that using a dedicated IP address for sending emails can improve your sender reputation and prevent your emails from being marked as spam. Monitor your IP reputation regularly.
Expert from Email Geeks suggests placing the MTA/Mail Server behind an IDS/IPS device to block DDOS attacks. They also suggest ensuring that the mail server is not configured as an open relay.
Email marketer from StackExchange suggests implementing connection limits and throttling mechanisms on the mail server to prevent overload during large email volumes or attacks.
Email marketer from AuthSMTP explains enabling TLS encryption for all email transmissions protects data in transit from eavesdropping. Using STARTTLS ensures secure communication between mail servers and clients.
What the experts say5Expert opinions
Expert from Email Geeks states that there is no way to hide the IP address of a mail server, other than having someone else host it.
Expert from Email Geeks explains that Cloudflare is a https proxy, not an SMTP proxy. It's designed for hiding abusive websites, not mail servers.
Expert from Spam Resource explains that one of the most effective steps to protect from email attacks is to rate limit connections. With Halon you would use the 'maxclients' setting under the 'listen' block to limit the number of concurrent connections.
Expert from Email Geeks suggests that outsourcing mail to a large-scale provider, such as Google or Fastmail, would enhance robustness. However, the ability to differentiate between wanted and unwanted mail will depend on the specifics.
Expert from Word to the Wise responds to the question of how to implement strict transport security which increases the security of mail connections. There is no link to 'Hide Mail Server' but increasing security will help mitigate attacks.
What the documentation says6Technical articles
Documentation from Cloudflare explains that Cloudflare can protect your server from DDoS attacks by acting as a reverse proxy. It filters malicious traffic and only allows legitimate requests to reach your server.
Documentation from Nginx explains implementing a reverse proxy configuration using Nginx to mask the actual mail server IP address and provide an additional layer of security. This involves configuring Nginx to forward requests to the mail server.
Documentation from DMARC.org explains that implementing DMARC (Domain-based Message Authentication, Reporting & Conformance) helps prevent email spoofing and phishing attacks. DMARC builds on SPF and DKIM to provide a more robust authentication mechanism.
Documentation from Spamhaus warns about the Spamhaus Block List (SBL) and its impact on email deliverability. Monitoring and preventing listing on SBL is crucial for ensuring emails reach their intended recipients.
Documentation from Microsoft Docs explains that you can harden Exchange Server by using strong passwords, disabling unnecessary services, keeping the server updated with the latest security patches, and configuring a firewall to restrict access to necessary ports.
Documentation from Postfix explains implementing rate limiting by configuring the `smtpd_client_connection_rate_limit` and related parameters to prevent abuse and overload. It also recommends using `fail2ban`.