While we do allow and fully support the use of static IPs when building a server/client branded pair, we officially prefer the use of an FQDN. We even fully support the use of dynamic IPs through the use of Dynamic Hostnames provided through Dynamic DNS services like DynDNS.
Why? There are several reasons:
1) Ease of use. For the same reasons that we would rather refer to a website by domain name than by IP address we find it easier to remember an FQDN than an IP address. An FQDN is easier to reference, discuss, and identify as well.
2) Moving the server. With an FQDN moving the server to a new IP is as easy as updating the DNS entry for the FQDN. On the other hand if you have addressed your client to the IP address of your server and you need to move the server to a different IP then the process is far more complicated:
• First you would need to build a new client that points to the new server.
• Next you would need to install the new client on all existing clients. This would then prevent them from backing up until the server was moved.
• Last, you would move the server. Ideally this would be done the same day that you updated all of the clients to prevent any missed backups.
Sounds like a mess, right?
3) Branding. Your FQDN becomes part of your brand. When performing troubleshooting in a support situation you are likely going to need to test the client connection to your backup server. It reinforces branding to say, or type, or otherwise communicate a branded FQDN (lets say 'backup.MYBRAND.com' for example). A plain old IPv4 address is just an uninteresting and hard to remember number.
4) You probably already have a website. Something like 'MYBRAND.com'. You can add unlimited subdomains to this domain (with most DNS hosts). So your backup server can then become and extention of your domain (ie: backup.MYBRAND.com). Likewise, when you inevitably need to expand and add a second (or third or more) backup server for redundancy or load-balancing you would more easily keep track of these assets by creating numbered FQDNs for each: backup.MYBRAND.com, backup2.MYBRAND.com, and backup3.MYBRAND.com (or maybe usa.MYBRAND.com, eu.MYBRAND.com, and in.MYBRAND.com if you are building out international or national distribution).
5) Round-Robin Load Balancing. Yes! When you use an FQDN you can create a VERY simple load-balancing scheme by adding multiple IP targets to the single sub-domain. This will cause subsequent requests to round-robin through the list of IPs and each of these IPs can point to a differnet server. For more info see How to load balance WholesaleBackup Servers.
Still want to use an IP? Go for it!
Need more info? What is an FQDN?