We currently have 2 ISPs & are using primary & secondary mx records for the same server - 220.127.116.11 pointing to mail.ourdomin.com & 18.104.22.168 pointing to mail1.ourdomain.com - both addresses are on our firewall which in turn forwards the relevant mail ports to the same one mail server's internal IP.
I'm supposed to swap between the 2 mx records so that the primary is secondary & vice versa (at the end of the year we'll stop working with the primary ISP, but for now both addresses are still operational).
1. Am I to expect a long downtime with sending & receiving emails? if so is it going to be the 24h to 48h of the mx change or will servers around the world still be using the old records they have & everything is expected to work till the swap actually take effect?
2. Am I required to do anything in addition to changing between the primary & secondary mx records with my domian's provider (Network Solutions)?
Thanks in advance!