LAN to Internet Connectivity
How Can We Connect The PCs On Our LAN To The Internet?
First We Must Find An ISP
Companies do not connect direct to the Internet. Instead they connect through an ISP – an Internet Service Provider. The ISP connects to the Internet and you connect to them.
What Kind Of Connection Will You Have To Your ISP?
The ISP will have different connection options. The faster the connection, the more users it will support AND the more it will cost, but Etisalat offers several
alternatives:
A 64 Kbps dial-up ISDN connection:
Installation Cost |
Rental per month in UAE DHS |
Dhs 1,000 |
Dhs 1085 giving 14 hours of usage per month |
or
Installation |
Rental per month UAE Dhs |
Dhs 1,000 |
Dhs 4000 |
Faster dedicated connections are also available:
Access Speed |
Monthly Rental |
Installation Charge |
128 K |
Dhs 10,000 |
Dhs 2,000 |
256 K |
Dhs 18,000 |
Dhs 4,000 |
512 K |
Dhs 30,000 |
Dhs 4,000 |
1 MB |
Dhs 45,000 |
Dhs 4,000 |
2 MB |
Dhs 70,000 |
Dhs 4,000 |
Above charges includes leased line & terminating modems |
||
See http://www.emirates.net.ae/ for further details
What Do You Need At Your End To Connect?
Software:
All of your machines that will access the Internet must have the TCP/IP protocol and web-browser software installed.
They will also all need IP addresses. These will be given to you by you ISP.
Hardware:
Unless you choose to use an ordinary dial-up telephone connects – which will be too slow to connect a whole LAN, the ISP will need to run a special cable to your office.
You will also need a modem CSU/DSU to connect the cable to your LAN.
Routing
The above setup still will not work.
The problem is to do with which packets are routed out of the LAN and on to the Internet.
We need a router.
There are many choices of what kind of router.
1. A dedicated, full-functionality router.
If the company already has a sophisticated router, maybe from Cisco or Bay-Networks, this can be used. This is what we do in HCT.
2. Use a server as a router.
A Windows NT server with multiple NICs and suitable software can act as a router. This is a cheap solution in a low traffic environment.
3. Use an Integrated modem/router.
Some companies sell ISDN adapters (modems) with built-in routing functionality. They typically cost less than $1000.
Proxy Servers
A proxy server is software. Logically, it goes between the Internet connection and the rest of the LAN.
It can do four things:
1. It can act as a cache, keeping local copies of frequently accessed pages.
2. It can act as a filter, blocking access to some sites.
3. It can keep records showing who accessed what.
4. It can include the functionality of a router, as described above.
Firewalls:
Remember that by default an Internet connection is two way. You can reach out, but others can reach in.
If you are worried about hackers accessing your corporate data you should use a firewall. A firewall is software (and maybe special hardware) that filters packets, to prevent unauthorized access to your network.
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