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WANGUARD 5.2 User Manual & Administrator's Guide
Appendix 1 – Network Basics You Should Be Aware Of
If you are new to network administraton and network monitoring, read about the technical basics in this
secton. It will help you understand how WANGUARD works. If you are already used to IP addresses and IP classes
you can safely skip this appendix.
IP Addresses
In order for systems to locate each other in a distributed environment, nodes are given explicit addresses
that uniquely identfy the partcular network the system is on and uniquely identfy the system to that partcular
network. When these two identfers are combined, the result is a globally-unique address. This address, known as
“IP address”, as “IP number”, or merely as “IP” is a code made up of numbers separated by three dots that identfes
a partcular computer on the Internet. These addresses are actually 32-bit binary numbers, consistng of the two sub
addresses (identfers) mentoned above which, respectvely, identfy the network and the host to the network, with
an imaginary boundary separatng the two.
An IP address is, as such, generally shown as 4 octets of numbers from 0-255 represented in decimal form
instead of binary form.
For example, the address 168.212.226.204 represents the 32-bit binary number
10101000.11010100.11100010.11001100.
The binary number is important because that will determine which class of network the IP address belongs
to. The Class of the address determines which part belongs to the network address and which part belongs to the
node address (see IP address Classes further on).
The locaton of the boundary between the network and host portons of an IP address is determined
through the use of a subnet mask. This is another 32-bit binary number which acts like a flter when it is applied to
the 32-bit IP address. By comparing a subnet mask with an IP address, systems can determine which porton of the
IP address relates to the network and which porton relates to the host. Anywhere the subnet mask has a bit set to
“1”, the underlying bit in the IP address is part of the network address. Anywhere the subnet mask is set to “0”, the
related bit in the IP address is part of the host address. The size of a network is a functon of the number of bits used
to identfy the host porton of the address. If a subnet mask shows that 8 bits are used for the host porton of the
address block, a maximum of 256 host addresses are available for that specifc network. If a subnet mask shows that
16 bits are used for the host porton of the address block, a maximum of 65,536 possible host addresses are available
for use on that network.
An Internet Service Provider (ISP) will generally assign either a statc IP address (always the same) or a
dynamic address (changes every tme one logs on). ISPs and organizatons usually apply to the InterNIC for a range
of IP addresses so that all clients have similar addresses. There are about 4.3 billion IP addresses. The class-based,
legacy addressing scheme places heavy restrictons on the distributon of these addresses. TCP/IP networks are
inherently router-based, and it takes much less overhead to keep track of a few networks than millions of them.
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