When setting up such things as your email accounts in Outlook, and remote access, use a name instead of the IP address if at all possible.
The reason for doing this, is that if your IP numbers change, as they will if you change your ISP, you will not have to change the IP address entered on all of your workstations. Instead, once the DNS entries have changed to reflect your new IP number(s), your email, and other applications, will work the same as they always have.
DNS entries are maintained by your system administrator. For Linux systems you normally find these in your /etc/bind directory. For Windows you should find this information in C:\Windows\System32\drivers\etc\hosts or similar location depending on the version of Windows.
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