An outline of tasks to consider and a timeline for switching your ISP (includes phone service switching too).

netCorps ISP Cutover Checklist

Note: This example references switching to Comcast as the new Internet service provider and telephone provider.


Cutover Date Minus 6 Weeks


– Map current phone numbers and Central Office (CO) lines being provided through current provider into current phone system. This may require calling in your phone system vendor for help in identifying which phone numbers go into which ports on your phone system.

– Make physical space in your equipment room for Comcast to mount a cable, a cable splitter, an Internet modem and Telephony modem. Mark *clearly* where you want this equipment to go otherwise the installer will simply mount things where convenient for *them*.


Cutover Date Minus 5 Weeks


– Order new Internet and phone service, set install date and verify all phone number “porting”. Porting is the term used in the telecom industry for moving a phone number from one telecom provider to another.

– Notify current telecom and Internet service provider that you will be cancelling service on the Cutover Date. Most vendors require 30 days notice or they charge a cancellation fee.

– Notify your accounting department of any cancellation or early contract termination fees. Accountants loathe unexpected expenses.


Cutover Date Minus 2 Weeks


– For In-House Mail Servers: Order and implement backup mail service and verify that backup mail service is working for the Fully Qualified Domain name (FQDN) of mail server(s) and *NOT* for hardcoded IP addresses. If your backup mail service must monitor a mail server IP addresses you may wish to find a new service.


Cutover Date Minus 1 Week


– Change any hardcoded e-mail link in website(s) to point to webmail server’s FQDN, (i.e. instead of hardcoded IP address.

– Create a DNS record for VPN connections rather than using a hard coded IP address.

– Remotely connect to all laptops and remote workstations to change hardcoded IP addresses in Outlook and VPN software to FQDN DNS records.

– Send out itinerary of Cutover and notice of service interruption to staff.


Cutover Date Minus 2 Days


– Update network map and documentation with new ISP and IP address information.

– Comcast installs Internet service at new location (WE ARE **NOT** PORTING PHONE NUMBERS TODAY! NO! NO!! NO!!! NO!!!! NO!!!!!)

– Verify VERIFY **VERIFY** that assigned static IP addresses work. Test the following:

* Can access outside IP addresses (i.e ping

* Can access outside domains (i.e. ping

* Run a speed test using one of the many speed test services ( has a few)

– Be certain that you record the following:

* Static IP Addresses

* Subnet mask

* Default gateway

* DNS server(s) IPs

– ** For In-House Mail Servers ** – Call Comcast and setup Reverse DNS entries


Cutover Date



– Connect Ethernet cable from new Internet service to firewall/router

– Reprogram firewall/router to use new WAN IP address, netmask, gateway, and DNS servers. If you are running a firewall on a Linux/unix box or a Microsoft ISA server this means changing the configuration of the External network connection to use the Comcast-assigned IP address, default gateway, and DNS server(s).

– Update ISA Server Web and Server Publishing Rules to reflect new IP addresses

– Update Internal DNS entries for in-house DNS server(s). Do this for all Internal DNS servers.

– Flush DNS cache on Internal DNS server(s). Do this for all Internal DNS servers.

– Test connection from firewall/router to outside world. Test outside IP addresses and domain names.

– Update external DNS A records referencing the old IP addresses to reference the corresponding new IP addresses

– ** For In-House Mail Servers ** – Update external DNS MX records referencing the old IP addresses to reference the corresponding new IP addresses

– ** For In-House Mail Servers ** – Update external SPF (TXT) record referencing the old IP addresses to reference the corresponding new IP addresses

– Test connection from all other Internal servers to outside world.

– Test connection from outside world to publicly addressable Internal server(s) (i.e. web server, mail server). NOTE: It may take a while for the DNS changes you made to propagate. Be a little patient. For a fast service like DNSMadeEasy expect 10-15 minutes.

– Test Internet connection to outside domains from a workstation.

– ** For In-House Mail Servers ** – Test mail service from a workstation.

– Change IP Address(es) for backup mail service if backup mail service requires hardcoded IP addresses instead of FQDN for mail server(s).

– Check backup mail service to see that held mail is now being forwarded to the in-house mail server.


– Connect CO lines to phone system

– Test outgoing phone lines

– Test incoming calling and auto-attendant

– Verify voicemail setup on primary Comcast phone number. In case the office phone system goes down Comcast can take messages for you. Comcast will not let you set this up until the phone numbers have been ported over.

– Train someone on how to retrieve messages from the Comcast voicemail system.


Cutover Date Plus 1 Day


– Schedule old ISP equipment removal

ISP Cutover Checklist