You need two entries in you hosts file and they are:
and that's all you need. I'm assuming you are behind a router or firewall because you have your DNS server on 127.0.0.1 (and you've already said so ). The external DNS indicates that you don't have any records set-up at all as per this report.
127.0.0.1 localhost.localdomain localhost
192..168.1.10 mx1.canmail.com mx1
From the zimbra server you can perform an initial test of the settings with the following:
From what you've posted you appear to be trying to use the public to resolve your server address, that's incorrect for your set-up. You need two different sets of DNS records. You need records in a public DNS server that point to your public IP address and you need records on your local DNS server that point to your LAN ip address. Please review the Split DNS set-up in the wiki.
host `hostname` <-- backticks not single quotes
dig computerking.ca mx
dig computerking.ca any