I support a small office of about 100 users. We run a small virtual environment and host our own on-premises Exchange server and Web Server.
We are in the process of upgrading our internet connection from a 100mpbs line on a 100mbps bearer to 200mbps on 1gbps bearer. I've been told by our ISP that since we are getting a new bearer, we will be getting a new block of static IP addresses.
Since we still host our own internal mail server and web server, we will need to update our public MX and A records accordingly. My question is, is there a way we could pre configure the MX record with the new IP address in advance so as to minimize downtime on our email when we come to install our new ISP provided router?
ie. Can I configure a second MX record with the new IP address before it is live so that when we make the switch, the first MX record dies and the second one works straight away?
I'm trying to avoid a situation where we have to switch the boxes, I change the MX record and it takes 24 hours to go live across public DNS servers. Leaving us with no email during that time.
The same also applies to a web server hosted on site. What is the best way to deal with the switch over in this case? I can only have one A record pointing to www.website.com, right? No way of having two A records configured and if one doesn't work, the other does?
Any help greatly appreciated.