Overview
The backup MX host must accept and queue mails, if the primary mailhost is down
for a certain domain. To have a high degree of availability the backup MX
host must be located outside the backed up domain. You can setup the
backup MX host as a primary or secondary mx for a remote site.
The primary mailhost is down ...
Email is delivered to the backup MX host
and queued there ....
After the primary mailhost is up and
running again, email is delivered from the backup MX host to the primary
mailhost and stored in the local mailboxes.
Setup of a primary mx host for a remote
site
IN MX 10 mail1.backup1.com.
IN MX 20 mail2.backup2.com.
All email for the remote site is
delivered to the primary mx host: mail1.backup1.com.
/etc/postfix/main.cf:
relay_domains = $mydestination
the.backed-up.domain.name
smtpd_recipient_restrictions = permit_mynetworks
check_relay_domains
/etc/postfix/main.cf:
transport_maps = hash:/etc/postfix/transport
/etc/postfix/transport:
the.backed-up.domain.name
smtp:[their.mail.host.name]
Setup of a secondary mx host for a remote site
IN MX 10 mail1.backup1.com.
IN MX 20 mail2.backup2.com.
All email for the remote site is
delivered to the secondary mx host: mail2.backup2.com.
/etc/postfix/main.cf:
relay_domains = $mydestination
the.backed-up.domain.name
smtpd_recipient_restrictions = permit_mynetworks
check_relay_domains
|