Zimbra Versoin: 8.8.15_GA_4272_FOSS
From the official wiki, I understand the config of zimbraDNSCHeckHostname is used if there is another MTA between Zimbra & the Internet (E.g. spam gateways).
However, after switching the MX record to the spam gateway and configuring Zimbra as the next-hop mail server inside the spam gateway. I discovered that emails can still be received from spam gateways to Zimbra even though I haven't setup the configuration in zimbraDNSCHeckHostname. So my question is whether the config zimbraDNSCHeckHostname is compulsory for using spam gateways and what would be impacted if missing out.
