About Dhcp; About Pppoe; About Domain Name Service (Dns); About Services And Policies - Watchguard Firebox X15 User Manual

Static and dynamic IP addresses
ISPs (Internet service providers) assign an IP address to each device on their network. The IP address can be
static or dynamic.
A static IP address is an IP address that always stays the same. If you have a web server, FTP server, or other
Internet resource that must have an address that cannot change, you can get a static IP address from your ISP.
A static IP address is usually more expensive than a dynamic IP address, and some ISPs do not supply static IP
addresses. You must configure a static IP address manually.
A dynamic IP address is an IP address that an ISP lets you use temporarily. If a dynamic address is not in use,
it can be automatically assigned to a different device. Dynamic IP addresses are assigned using either
DHCP or PPPoE.

About DHCP

Dynamic Host Configuration Protocol (DHCP) is an Internet protocol that computers on a network use to get
IP addresses and other information such as the default gateway. When you connect to the Internet, a
computer configured as a DHCP server at the ISP automatically assigns you an IP address. It could be the same
IP address you had before, or it could be a new one. When you close an Internet connection that uses a
dynamic IP address, the ISP can assign that IP address to a different customer.
You can configure the Firebox as a DHCP server for networks behind the Firebox. You assign a range of
addresses that the DHCP server can choose from.

About PPPoE

Some ISPs assign their IP addresses through Point-to-Point Protocol over Ethernet (PPPoE). PPPoE expands a
standard dial-up connection to add some of the features of Ethernet and PPP. This network protocol allows
the ISP to use the billing, authentication, and security systems of their dial-up infrastructure with DSL modem
and cable modem products.

About Domain Name Service (DNS)

If you do not know the address of a person, you can frequently find it in the telephone directory. On the
Internet, the equivalent to a telephone directory is the DNS (Domain Name Service). Each web site has a
domain name (such as mysite.com) that maps to an IP address. When you type a domain name to show a web
site, your computer gets the IP address from a DNS server.
A URL (Uniform Resource Locator) includes a domain name and a protocol. An example of a URL is:
http://www.watchguard.com/.
In summary, the DNS is the system that translates Internet domain names into IP addresses. A DNS server is a
server that performs this translation.

About services and policies

You use a service to send different types of data (such as email, files, or commands) from one computer to
another across a network or to a different network. These services use protocols. Frequently used Internet
services are:
User Guide
Introduction to Network Security
5