Mushroom Networks Documentation

SMTP failover

SMTP failover would require both the outgoing and incoming configuration.


Set the Reverse DNS with multiple IPs (WAN1, WAN2, etc) pointing to the same domain


Followiing example taken from:

You can specify MX records for a single Internet domain — for example, — with a single Internet domain name, such as Use the server’s fully-qualified Internet host name in the MX and A records — for example,

For example, configure a backup SMTP server ( to deliver or forward mail when the primary SMTP server ( is unavailable:

    1. MX record: IN MX 5

A record: IN A

    1. MX record: IN MX 10

A record: IN A

Messages addressed to route to first because the record’s preference (5) is lower. If is unavailable, mail is routed to


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