I have a client with 15 email addresses on thieir domain. They want to use Google Apps mail for 4 of those addresses and leave the rest on their current POP server.
I'm not sure how DNS works here. I understand that the MX records are setup with a priority. If I have an MX record with priority of 1 pointing to thir current POP server and the Google Apps MX records starting from a priority of 2, for addresses that don't exist on the POP server will this try to deliver to the POP server, get an NDR and then try the Google servers? or have I got this all wrong.
I have a feeling the the priority is just the order of the servers that will be tried to send the mail. If it connects to the POP server we will just get an NDR.
Any advice highly appreciated.