Google Apps and Mailsphere
You can use Google Apps for business (Gmail) with Mailsphere.
Setting Up Mailsphere
After the organisation has been configured the following set up should be performed in Domains for that Organisation.
Domain - Incoming Configuration
The incoming IP addresses actually have to be any of Googles mail servers. Currently the following IP addresses need to be added as the Incoming servers:
Domain - Outgoing Configuration
The outgoing IP addresses are defined here: http://support.google.com/a/bin/answer.py?hl=en&answer=174125
Mailsphere supports DNS names as well as IP addresses so these are fine to put straight in.
Currently the values are:
Setting up Google Apps
1) Setup Google apps to use mailsphere as a “outbound mail gateway” http://support.google.com/a/bin/answer.py?hl=en&answer=178333
Use the standard Mailsphere IP address/addresses/load balancer as the destination.
2) Ensure that Google apps forwards all internal email via this gateway too.