Network Addressing; About Dhcp; About Pppoe; Default Gateway - Watchguard Firebox X20E User Manual

Domain Name Service (DNS)

Network addressing

ISPs (Internet service providers) assign an IP address to each device on their network. The IP address
can be static or dynamic. Each ISP has a small number of IP addresses.
Static IP addresses are permanently assigned to a device. These addresses do not change automati-
cally, and are frequently used for servers.
Dynamic IP addresses are assigned automatically and can change with time. If a dynamic address is not
in use, it can be automatically assigned to a different device.
Your ISP can tell you how their system assigns IP addresses.

About DHCP

Many ISPs assign dynamic IP addresses through DHCP (Dynamic Host Configuration Protocol). When a
computer connects to the network, a DHCP server at the ISP automatically assigns that computer an IP
address. It is not necessary to assign IP addresses manually when you use DHCP.

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 infra-
structure with DSL modem and cable modem products.

Default gateway

A default gateway is a node on a computer network that serves as an access point to another network.
Usually, the default gateway address is the IP address of the router that is between your network and
the Internet. After you install the Firebox X Edge on your network, the Edge acts as the default gateway
for all computers connected to its trusted or optional interfaces.
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.

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:
World Wide Web access uses Hypertext Transfer Protocol (HTTP)
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4 Firebox X Edge e-Series