what is the advantage of having a static IP

There is no reason to consider that either a static or dynamic IP address are better than the other, because it all depends on what you personally prefer. Your IP address is the address used to locate and identify your computer on the internet or on a network, and as far as the internet is concerned it is the IP address supplied by your ISP. You can usually choose between having a static IP which will be the same on a permanent basis, or a dynamic IP which will be different every time you log on to the ISP. If you choose to access your computer remotely from elsewhere, then you will require a static IP address to create the Virtual Private Network to link with. If you choose a dynamic IP then others will not be able to locate your computer easily and this increases security.

It is great if you are running WAMP/XAMP etc.

A static IP is beneficial when running a server, file sharing program, or during online gaming. If you are running a server you want a static IP so computers can be preconfigured to connect to the server. If the IP is dynamic the computers will have to search for and find the server every time they connect. For file sharing a static IP allows your computer to connect more easily to the sharing network. It also allows port forwarding to work more effectively. If you are using a Bittorrent client your download speeds will be greatly increased by using a static IP. If you are using a laptop with a wireless connection and you travel a lot you should not set it to static IP. that will make it difficult or impossible to connect to some networks. Also, if you have a network with multiple computers, they should all be dynamic, or all static. Mixing dynamic and static can cause problems if more than one computer tries to use the same IP.

I was told by my ISP that a static IP is only important if you want to host your own domain on your computer instead of paying for a hosting company, all sites must have static IPs for people to reach them. I don't know of any other benefit for a static IP but the down side to it is you can be blocked or banned easily by any site or service by blocking your static IP. For dynamic IPs, every time you connect to the net you get a different IP and there's no down side to this that I know of because most people will not run a server 24/7 and host websites on their computers.

An IP (Internet Protocol) address uniquely distinguishes your node from anyother on the internet. The address can be either dynamic or static; the differences and the pros and cons of each type are discussed below. Most people at Fermilab use Dynamic IP addresses, known as DHCP addresses (for Dynamic Host Configuration Protocol). This is at least partly because W2K networking has been built around the use of DHCP for workstations, and DHCP provides reliable and simple TCP/IP network connections. Dynamic IP (DHCP) Address Each time a DHCP client boots, it sends out a DHCP discover message. All DHCP servers answer (in practice only one is set to do this at Fermilab; in the future possibly a second will be added for redundancy) with an offer message that includes an address which is available to the client. The client machine typically repeats the discover message several times to make sure it hears from all the servers, then eventually chooses the “best” server, where what is “best” is up to the client. It may mean that the addresses the DHCP server has available offer the longest lease time. Or the client might prefer a server that provides WINS servers over one that doesn’t (the WINS servers keep track of all the clients’ and servers’ latest dynamic IP addresses). The currently active DHCP server is configured by hand to handle and reserve IP addresses and the IP configuration information that goes with them. Addresses are made available in an order that permits a client to have the best chance of getting back the same address it was using most recently. To this end, the DHCP server offers its least recently used address to a new client. Once the client chooses a DHCP server, it “officially” requests the IP address and configuration information. In addition to this, it receives a lease time for the address. This lease time is not absolute. As long as it is running, the client machine requests renewal of the lease. This is invisible to the user, although there is a mechanism for the user to release the address early (ipconfig/release from the command prompt) or to renew it (ipconfig/renew). Client machines in the FERMI domain typically access multiple file servers, print servers, and so on. The clients as well as the servers may change their IP addresses. Via the WINS servers, this is transparent to the user. Advantages 1) All the IP configuration information gets automatically configured for your client machine by the DHCP server. 2) If you move your client machine to a different subnet, the client will send out its discover message at boot time and work as usual. However, when you first boot up there you will not be able to get back the IP address you had at your previous location regardless of how little time has passed. 3) DHCP can be used with Kerberos authentication; just be aware that any time your address changes, you’ll need to reauthenticate to Kerberos. This is true for the FERMI (W2K) domain as well as for the FNAL (UNIX) domain if you’ve logged onto a remote UNIX host. Disadvantage Your machine name does not change when you get a new IP address. The DNS (Domain Name System) name is associated with your IP address and therefore does change. This only presents a problem if other clients try to access your machine by its DNS name. Static IP Address If you have requested a static IP address on the Node Registration Form, you need to wait for the reply with all the information you need to use for configuring your server machine. Once you receive it, under Windows, delve down to START/SETTINGS/CONTROL PANEL/NETWORK/PROTOCOLS and enter the information that you received. Configuring your machine for a static IP address requires filing for an exemption under the Fermilab Policy on Computing, see Obtaining an Exemption from the Policy at http://www.fnal.gov/docs/strongauth/html/policy.html #39728. Advantage • The two names (Windows name and DNS name) are the same as each other, and neither ever changes. Other clients may therefore reliably access your machine by its DNS name. Disadvantages 1) You can’t move your machine to a different subnet and expect it to work. You need to reconfigure it. 2) If machines come and go, or are up only some of the time, static assignments are less resource-efficient (where the resource in question is the IP address itself).