Lets say Company X is changing ISP’s, hence changing public static IP’s. They have a web server and a mail server on the same machine, but not on the domain (that will be another thread) and a DNS server on the domain that serves ~50 users. And using a sonicwall firewall. what things should said Company X be doing to ensure a smooth transition? thanks ahead of time.
1. Should Reverse DNS be set on both servers and also with the ISP?
2. How should one ensure that MX Records and Nameservers are updated/consistent? The email is filtered by MX Logic before hitting the local server….what should be updated in that account?
3. Besides opening port 53 UDP/TCP on firewall, can one just simply replace the old public IP with the new one in all objects/rules, etc?
4. What kinds of changes to the NAT policy should be made, if any?
5. What else should be considered to make the change transparent.
keep in mind that an “extra” or backup DNS server is not available….
does anyone have a checklist or a link about this?
grazie molto