Anti-Hacker.Toolkit.3rd.Ed.ebook-Spy

wah..macam menarik je topik ni..sesapo tak baco memang rugi..kekeke..ni terd0wnl0ad pulok satu ebook punco ae nak d0wnl0ad manual freeBSD p terd0wnl0ad pulak ebook ni.



sesapo nak bagitau lah..den ado lotak kek mediafire..

http://www.mediafire.com/?94u20y9pqdy758e

Subnetting Concept

Subnetting makes it possible to divide a large network IP address space into several smaller,more manageable "subnets."

The example on the slide shows a subnetted /16 network. Without subnetting, the 128.1.0.0/16 network would have 65 thousand hosts on the same physical network, which could easily lead to excessive collisions

This network, however, has been subdivided into 254 subnets. Each of these subnets could potentially have up to 254 hosts.

Subnet Addresses
----------------
128.1.1.0
128.1.2.0
...
128.1.253.0
128.1.254.0

Subnets are separated from one another by routers, which overcome both the collision and topological issues discussed on the previous slide.

Subnetting also makes it easy for the network administrator to delegate authority for
portions of the IP network address space to other entities within the organization. Simply assign each department a separate subnet. Each network administrator then becomes responsible for a subnet within the larger corporate network

Limitations of Large Networks

Although a /8 network address allows for 16 million host addresses, in reality, it is impractical to have that many hosts sharing a single physical network

Topological Limitations
Many LAN topologies don't allow 16 million nodes on a single physical network.Excessive Collisions If any two nodes on an ethernet network transmit at the same instant, a collision results and both nodes must attempt to retransmit. As the number of nodes on the network increases,the likelihood of collisions increases as well.Administrative Challenges Simply keeping track of who has which IP address in a 16- million node network would be an administrative challenge for even the best network administrator.Poor Network Performance All of these issues result in degraded network performance as more and more hosts compete for limited bandwidth on a network

Excessive Collisions
If any two nodes on an ethernet network transmit at the same instant, a collision results and both nodes must attempt to retransmit. As the number of nodes on the network increases,the likelihood of collisions increases as well

Administrative Challenges
Simply keeping track of who has which IP address in a 16- million node network would mbe an administrative challenge for even the best network administrator

Poor Network Performance
All of these issues result in degraded network performance as more and more hosts compete for limited bandwidth on a network.

Managing Packet Flow with TCP

Obtaining an IP Address

ni nak share tentang ip addres..macamana proses dari private IP ke public IP



These organizations, in turn, allocate blocks of public Internet IP addresses to corporations and Internet Service Providers. Check with your local IT department or ISP to obtain an address on the public Internet.Connecting to a private Intranet with an Internet Address Many organizations choose not to connect individual hosts directly to the public Internet for security reasons. Why expose your hosts to thousands of hackers, if those hosts need only limited access to the outside networks? Instead, many organizations choose to configure a private Intranet that is insulated from the dangers of the public Internet by some sort of network firewall. Firewalls can be used to control the type of traffic that passes both in and out of your organization's private Intranet.There are two ways to obtain and allocate IP addresses in this situation. One approach is to request a public Internet IP address for each host, then shield those hosts behind your firewall. If you choose to go this route, you will have to apply for a block of unique, public Internet addresses from your ISP or the websites listed in the previous section.

Connecting to a private Intranet Using Network Address Translation

Since public Internet IP addresses are in short supply, many organizations choose instead to provide Internet access to their internal hosts using some sort of proxy server software,which does not require a unique Internet address for every host on the private Intranet. Using this approach, hosts on your private Intranet are assigned addresses from the following
blocks of IPs:
10.*.*.*
172.16-31.*.*
192.168.*.*
These addresses are designated specifically for use on private Intranets. Hosts with
addresses within these ranges may not be connected directly to the public Internet, nor are packets destined for these addresses allowed to pass on or through the public Internet. Since these addresses are not allowed directly on the public Internet, any organization may use these addresses without fear of conflicting with other organization's addresses.
Question: If packets destined for these addresses are not allowed on the public Internet, how can these hosts send email or access web sites outside their private networks?
Intranet hosts that need web access to the outside world may access the Internet via a proxy server. These hosts can be configured to relay all external web access requests through a specially configured server with connections both to the private Intranet, and the public Internet. The proxy server forwards internal clients' access requests to external sites via its IP address on the public Internet, then relays the responses back to the requesting clients. Email service may be provided using similar functionality. Hosts on the private Intranet send and receive email via a specially configured Mail Gateway that straddles both the private Intranet, and the public Internet.

IP LOOPBACK ADDRESS

BROADCAST

salam semuo..dah lamo tak update blog den sobab sibuk dongan kerja training.dari training yang aku pegi aku akan share sedikit mengenai broadcast..