Zimbra as primary - do the forwarded mails go through antispam?

[Yann2]

Hello, we are currently using Zimbra as a secondary mail server, for testing and making a smooth migration, moving one user at a time from Exchange to Zimbra. Our online antispam service will expire soon though (we are using blackspider), and we don't want to renew it as it is quite expensive - so we would like to use Zimbra's antispam feature.

So we want to put Zimbra as primary, and our Exchange server as secondary; that way Zimbra could filter the spam before it get delivered to exchange.

So here is my question: does Zimbra filters spam on mails to mailboxes it is supposed to forward to?

[phoenix]

Zimbra filters anything that hits port 25 before it gets delivered or forwarded.

[Yann2]

Hello, thanks for your answer

[mdeneen]

If by secondary, you mean a different MX priority in DNS, be careful. A lot of spammers target the backup mail servers because there is a greater chance of less spam filtering.

In the past, I have seen places which have their primary with the spam filter, and a secondary without spam filtering blocked by the firewall. In the event of an emergency, where the primary had failed, the secondary firewall rule would be removed.

Mark