Page 56 / 335 Scroll up to view Page 51 - 55
Vigor2710 Series User’s Guide
44
the 2nd subnet with neighboring routers.
DHCP Server
Configuration
DHCP stands for Dynamic Host Configuration Protocol. The
router by factory default acts a DHCP server for your network so
it automatically dispatch related IP settings to any local user
configured as a DHCP client. It is highly recommended that you
leave the router enabled as a DHCP server if you do not have a
DHCP server for your network.
If you want to use another DHCP server in the network other
than the Vigor Router’s, you can let Relay Agent help you to
redirect the DHCP request to the specified location.
Enable Server -
Let the router assign IP address to every host in
the LAN.
Disable Server –
Let you manually assign IP address to every
host in the LAN.
Relay Agent – (1
st
subnet/2
nd
subnet)
Specify which subnet that
DHCP server is located the relay agent should redirect the DHCP
request to.
Start IP Address -
Enter a value of the IP address pool for the
DHCP server to start with when issuing IP addresses. If the 1st IP
address of your router is 192.168.1.1, the starting IP address must
be 192.168.1.2 or greater, but smaller than 192.168.1.254.
IP Pool Counts -
Enter the maximum number of PCs that you
want the DHCP server to assign IP addresses to. The default is 50
and the maximum is 253.
Gateway IP Address -
Enter a value of the gateway IP address
for the DHCP server. The value is usually as same as the 1st IP
address of the router, which means the router is the default
gateway.
DHCP Server IP Address for Relay Agent -
Set the IP address
of the DHCP server you are going to use so the Relay Agent can
help to forward the DHCP request to the DHCP server.
DNS Server
Configuration
DNS stands for Domain Name System. Every Internet host must
have a unique IP address, also they may have a human-friendly,
easy to remember name such as www.yahoo.com. The DNS
server converts the user-friendly name into its equivalent IP
address
.
Force DNS manual setting -
Force Vigor router to use DNS
servers in this page instead of DNS servers given by the Internet
Access server (PPPoE, PPTP, L2TP or DHCP server).
Primary IP Address -
You must specify a DNS server IP address
here because your ISP should provide you with usually more than
one DNS Server. If your ISP does not provide it, the router will
automatically apply default DNS Server IP address: 194.109.6.66
to this field.
Secondary IP Address -
You can specify secondary DNS server
IP address here because your ISP often provides you more than
one DNS Server. If your ISP does not provide it, the router will
automatically apply default secondary DNS Server IP address:
Page 57 / 335
Vigor2710 Series User’s Guide
45
194.98.0.1 to this field.
The default DNS Server IP address can be found via Online
Status:
If both the Primary IP and Secondary IP Address fields are left
empty, the router will assign its own IP address to local users as a
DNS proxy server and maintain a DNS cache.
If the IP address of a domain name is already in the DNS cache,
the router will resolve the domain name immediately. Otherwise,
the router forwards the DNS query packet to the external DNS
server by establishing a WAN (e.g. DSL/Cable) connection.
There are two common scenarios of LAN settings that stated in Chapter 5. For the
configuration examples, please refer to that chapter to get more information for your
necessity.
3.3 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.
Page 58 / 335
Vigor2710 Series User’s Guide
46
3.3.1 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.
Page 59 / 335
Vigor2710 Series User’s Guide
47
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.
Page 60 / 335
Vigor2710 Series User’s Guide
48
3.3.2 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.
The inherent 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:
If you previously have set up
WAN Alias
for
PPPoE/PPPoA
or
MPoA
mode
,
you will find
them in
Aux. WAN IP
for your selection.

Rate

4.5 / 5 based on 2 votes.

Bookmark Our Site

Press Ctrl + D to add this site to your favorites!

Share
Top