DrayTek Vigor 2830 Router Manual PDF (Setup & Configuration Guide)

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IP Bind List

It displays a list for the IP bind to MAC information.

Add

It allows you to add the one you choose from the ARP table or the

IP/MAC address typed in

Add and Edit

to the table of

IP Bind

List

.

Edit

It allows you to edit and modify the selected IP address and MAC

address that you create before.

Delete

You can remove any item listed in

IP Bind List

. Simply click and

select the one, and click

Delete

. The selected item will be

removed from the

IP Bind List

.

Note:

Before you select

Strict Bind

, you have to bind one set of IP/MAC address for one

PC. If not, no one of the PCs can access into Internet. And the web configurator of the router

might not be accessed.

4.3 NAT

Usually, the router serves as an NAT (Network Address Translation) router. NAT is a

mechanism that one or more private IP addresses can be mapped into a single public one.

Public IP address is usually assigned by your ISP, for which you may get charged. Private IP

addresses are recognized only among internal hosts.

When the outgoing packets destined to some public server on the Internet reach the NAT

router, the router will change its source address into the public IP address of the router, select

the available public port, and then forward it. At the same time, the router shall list an entry in

a table to memorize this address/port-mapping relationship. When the public server response,

the incoming traffic, of course, is destined to the router’s public IP address and the router will

do the inversion based on its table. Therefore, the internal host can communicate with external

host smoothly.

The benefit of the NAT includes:

z

Save cost on applying public IP address and apply efficient usage of IP address.

NAT allows the internal IP addresses of local hosts to be translated into one public IP

address, thus you can have only one IP address on behalf of the entire internal hosts.

z

Enhance security of the internal network by obscuring the IP address.

There are

many attacks aiming victims based on the IP address. Since the attacker cannot be aware

of any private IP addresses, the NAT function can protect the internal network.

On NAT page, you will see the private IP address defined in RFC-1918. Usually we use the

192.168.1.0/24 subnet for the router. As stated before, the NAT facility can map one or

more IP addresses and/or service ports into different specified services. In other words, the

NAT function can be achieved by using port mapping methods.

Below shows the menu items for NAT.

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4.3.1 Port Redirection

Port Redirection

is

usually set up for server related service inside the local network (LAN),

such as web servers, FTP servers, E-mail servers etc. Most of the case, you need a public IP

address for each server and this public IP address/domain name are recognized by all users.

Since the server is actually located inside the LAN, the network well protected by NAT of the

router, and identified by its private IP address/port, the goal of Port Redirection function is to

forward all access request with public IP address from external users to the mapping private IP

address/port of the server.

The port redirection can only apply to incoming traffic.

To use this function, please go to

NAT

page and choose

Port

Redirection

web page. The

Port Redirection Table

provides 20 port-mapping entries for the internal hosts.

Press any number under Index to access into next page for configuring port redirection.

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Enable

Check this box to enable such port redirection setting.

Mode

Two options (Single and Range) are provided here for you to

choose. To set a range for the specific service, select

Range

. In

Range mode, if the public port (start port and end port) and the

starting IP of private IP had been entered, the system will

calculate and display the ending IP of private IP automatically.

Service Name

Enter the description of the specific network service.

Protocol

Select the transport layer protocol (TCP or UDP).

WAN IP

Select the WAN IP used for port redirection. There are eight

WAN IP alias that can be selected and used for port redirection.

The default setting is

All

which means all the incoming data from

any port will be redirected to specified range of IP address and

port.

Public Port

Specify which port can be redirected to the specified

Private IP

and Port

of the internal host. If you choose

Range

as the port

redirection mode, you will see two boxes on this field. Simply

type the required number on the first box. The second one will be

assigned automatically later.

Private IP

Specify the private IP address of the internal host providing the

service. If you choose

Range

as the port redirection mode, you

will see two boxes on this field. Type a complete IP address in the

first box (as the starting point) and the fourth digits in the second

box (as the end point).

Private Port

Specify the private port number of the service offered by the

internal host.

Note that the router has its own built-in services (servers) such as Telnet, HTTP and FTP etc.

Since the common port numbers of these services (servers) are all the same, you may need to

reset the router in order to avoid confliction.

For example, the built-in web configurator in the router is with default port 80, which may

conflict with the web server in the local network, http://192.168.1.13:80. Therefore, you need

to

change the router’s http port to

any one other than the default port 80

to avoid conflict,

such as 8080. This can be set in the

System Maintenance >>Management Setup

. You then

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will access the admin screen of by suffixing the IP address with 8080, e.g.,

http://192.168.1.1:8080 instead of port 80.

4.3.2 DMZ Host

As mentioned above,

Port Redirection

can redirect incoming TCP/UDP or other traffic on

particular ports to the specific private IP address/port of host in the LAN. However, other IP

protocols, for example Protocols 50 (ESP) and 51 (AH), do not travel on a fixed port. Vigor

router provides a facility

DMZ Host

that maps ALL unsolicited data on any protocol to a

single host in the LAN. Regular web surfing and other such Internet activities from other

clients will continue to work without inappropriate interruption.

DMZ Host

allows a defined

internal user to be totally exposed to the Internet, which usually helps some special

applications such as Netmeeting or Internet Games etc.

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The security properties of NAT are somewhat bypassed if you set up DMZ host. We suggest

you to add additional filter rules or a secondary firewall.

Click

DMZ Host

to open the following page:

DMZ Host for WAN2 and WAN3 is slightly different with WAN1.

Active True IP

selection

is available for WAN1 only.

See the following figure.

Rate

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