INTELLINET NETWORK 524988 User Manual - Manual (Page 45)

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ADVANCED FUNCTIONS
Local IP Address — Specify the local (source) IP address that will be affected by
this rule. Enter the starting IP address in the left field, and enter the end address
in the right field to define a range of IP addresses; or just enter the IP address in
the left field to define a single IP address.
Local Port Range — Enter the range of local (source) port numbers that should be
affected by this rule. To apply this rule on ports 80 to 90, enter “80-90”; to apply
this rule only to a single port, just enter the port number, such as “80.”
Remote IP Address — Specify the remote (destination) IP address that should be
affected by this rule. Enter the starting IP address in the left field, and enter the
end address in the right field to define a range of IP addresses; or just enter the
IP address in the left field to define a single IP address.
Remote Port Range — Enter the range of remote (destination) port numbers that
should be affected by this rule. To apply this rule on ports 80 to 90, enter “80-90”;
to apply this rule only to a single port, just enter the port number, such as “80.”
If the remote (destination) IP address and/or port number is universal, just leave
it blank.
Traffic Type — Select the traffic type of this rule from the drop-down menu: “None,”
“SMTP,” “HTTP,” “POP3” or “FTP.” To make this rule an IP address-based rule
(to apply the limitation on all traffic from/to the specified IP address or port
number), select “None.”
Protocol — Select the protocol type of this rulefrom the drop-down menu: “TCP” or
“UDP.” If you don’t know what protocol your application uses, try “TCP” first and
switch to “UDP” if this rule doesn’t seem to work.
Click “Save” to add the new rule. It will appear in the current QoS table. Should an
error message show up after you click “Save,” you can try again, but fixing the
problem first and then clicking “Save” will have a better chance of working.
To erase all values you’ve entered, click “Reset.”
3.2 Network Address Translation (NAT)
Network Address Translation (NAT, also known as Network Masquerading, Native
Address Translation or IP Masquerading) is a technique of transceiving network
traffic through a router that involves re-writing the source and/or destination IP
addresses and usually the TCP/UDP port numbers of IP packets as they pass
through. Checksums (both IP and TCP/UDP) must also be rewritten to take account
of the changes. Most systems using NAT do so in order to enable multiple hosts
on a private network to access the Internet using a single public IP address (see
gateway). Many network administrators find NAT a convenient technique and use
it widely. Simply put: The router’s NAT function allows the connection of multiple
computers to one Internet line.