In the first message it says:
basically this means that if the servers firewall has an Access Control List to restrict inbound traffic, you will need to take action and update the ACL list to include the new IP addresses.
This is a server configuration issue, so you will not need to do anything on your part, but your host may need to update the ACL list on the firewall.
The second link is a notice of downtime for the Payflow Pro System.
the third link is a duplicate of the first.