Package 1 · Backup MX
Secondary MX, temporary queuing during destination outages and automatic delivery on recovery. No mailbox pre-check, AntiSpam, Antivirus, content inspection or quarantine.
TECHNICAL GUIDES
MX Priorities and Multiple Mail Servers
Understand preference numbers, equal-priority records and secondary MX placement.
Package 2 · Email Protection
Primary MX gateway with configurable AntiSpam, Antivirus, sender-domain checks and quarantine. Publish only gate.securawall.com and configure a separate manual receiving target. Queuing and recovery remain included.
Optional SMTP Relay add-on
Add authorized outbound delivery to either Package 1 or 2 for the same domain. Separate add-on pricing, approval, server credentials, quotas, TLS and verified SPF apply. Customer-domain DKIM signing is optional and recommended. Incoming protection remains determined by the base package.
Explore packages and add-ons
By the SecuraWall team · Updated · Operational guidance, not a delivery guarantee.
Lower numbers are preferred
MX records have a numeric preference. Lower numbers are preferred for SMTP routing. If legitimate primary records use 10 and 20, a backup preference of 30 places it after both. These numbers describe routing preference; they are not uptime scores or waiting times.
Keep legitimate primary records
Do not delete Google Workspace, Microsoft 365 or other legitimate primary MX records just to add a backup. A domain with several primary targets still needs one domain plan, not a plan per MX hostname. Review all intended primary preferences before choosing a backup number.
Equal preference is not a backup marker
Two records with the same preference do not establish a strict primary-then-backup relationship. Publishing multiple hostnames also does not prove separate data centers. A domain owner needs to know how those mail servers and their queues are actually operated.
Avoid routing loops
Your backup delivery target must be the real destination, not the backup gateway again. SecuraWall automatic mode excludes its own gateway and uses eligible primary MX destinations. Manual mode should point to the public receiving host and port. Confirm discovered targets after saving.
SPF and Null MX are different records
SPF does not choose MX priority. A Null MX record advertises that the domain does not accept email. Do not attach a receiving backup service to a Null MX policy without deliberately changing that policy. No explicit MX does not always mean no mail: address-record fallback is a separate SMTP behavior.
Inspect before changing DNS
Use the free Domain Check to inspect public preference numbers and target addresses. Optional inline SMTP tests observe reachability and TLS without submitting mail; they do not prove recipient acceptance. Save the original records and validate the resulting configuration in your account before relying on it.
References and service conditions
Related guides
Backup MX with Multiple Primary Mail Servers
Plan secondary routing for several legitimate primary destinations without loops or extra domain subscriptions.
Read guide →How to Test Backup MX Safely
Validate your own domain, queue behavior and recovery without treating an open port as successful delivery.
Read guide →Backup MX Queue Retention and Deletion
Understand message age, expiry, paused delivery and permanent queue removal.
Read guide →