I need to solve a real doubt before making modifications at my DNS in a Linux Server.
All my domains files at /var/named have lines like these:
www IN A 220.127.116.11
ftp IN A 18.104.22.168
mail IN A 22.214.171.124
smtp IN A 126.96.36.199
I was asked by the ISP to modify them to some like these:
www IN CNAME srv1.multisitesdominios.com.br.
ftp IN CNAME srv1.multisitesdominios.com.br.
mail IN CNAME srv2.multisitesdominios.com.br.
smtp IN CNAME srv6.multisitesdominios.com.br.
They say that in this way I will not be dependent on any IP modification they do. My questions:
No problem about this? Wouldn't my DNS work more slowly? Please I would like to know, technically, what is the difference between "IN A" records and "IN CNAME" records.