Solwise Ltd., www.solwise.co.uk, sales@solwise.co.uk
- 32 -
The term gateway is used generically to mean the device that connects a local network
to the Internet. A gateway may be a router, a PC running software which allows it to act
as a gateway such as a proxy server, or some other device. Most home networks use a
NAT (Network Address Translation) router as a gateway. The term gateway router refers
to such a device.
Static versus Dynamic IP address
The IP address (or addresses) your ISP has provided you will either be static, which
means it never changes, or dynamic, meaning it can change periodically. Dynamic
addresses present an additional challenge when trying to locate your network from the
Internet since your address may have changed since the last time you checked it. How
often your dynamic address changes vary from one service provider to another. Also,
any time you reboot your cable or DSL modem, your are likely to get a new address
when reconnecting. The solution to the ever changing IP address is known as DDNS or
dynamic domain name service. A DDNS will allow you to find your network by a domain
name, such as c1060-id.vipcam.cn
, rather than needing to know the IP address.
6.2 Network Address Translation (NAT)
Most home routers and business firewalls today perform something called NAT or
Network Address Translation. NAT translates your external or WAN IP address into an
internal address inside your gateway router. What this means is, you can think of your
router as being divided into two halves, the LAN side (inside) and the WAN side (outside
or Internet side). When a connection request arrives at your router from the Internet, it
will not get any farther than the WAN side unless you have specifically instructed your
router to pass this type of request to a specific device on your LAN. This process is
known as port forwarding or port redirecting.
To Next Page
Loading...