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MTU:

The Maximum Transmission Unit (MTU) is a parameter that determines the largest

packet size (in bytes) that the router will send to the WAN. If LAN devices send larger

packets, the router will break them into smaller packets. Ideally, you should set this to

match the MTU of the connection to your ISP. Typical values are 1500 bytes for an

Ethernet connection and 1492 bytes for a PPPoE connection. If the router's MTU is set

too high, packets will be fragmented downstream. If the router's MTU is set too low, the

router will fragment packets unnecessarily and in extreme cases may be unable to

establish some connections. In either case, network performance can suffer.

MAC Address:

Each networking device has it's own unique MAC address defined by the

hardware manufacturer. Some ISP's may check your computer's MAC address. Some

ISP's record the MAC address of the network adapter in the computer or router used to

initially connect to their service. The ISP will then only grant Internet access to requests

from a computer or router with this particular MAC address. This router has a different

MAC address than the computer or router that initially connected to the ISP. If you need

to change the MAC address of the rounter's WAN-side Ethernet interface, either type in

an alternate MAC address (for example, the MAC address of the router initially connected

to the ISP) or copy the MAC address of a PC. To copy the MAC address of the computer

that initially connected to the ISP, connect to the router using that computer and click the

Clone Your PC's MAC Address

button. The WAN interface will then use the MAC

address of the network adapter in your computer.

NETWORK

Router Settings

These are the settings of the LAN (Local Area Network) interface for the router. The

router's local network (LAN) settings are configured based on the IP Address and Subnet

Mask assigned in this section. The IP address is also used to access this Web-based

management interface. It is recommended that you use the default settings if you do not

have an existing network.

IP Address

The IP address of your router on the local area network. Your local area network settings

are based on the address assigned here. For example, 192.168.0.1.

Subnet Mask

The subnet mask of your router on the local area network.

Local Domain Name

This entry is optional. Enter a domain name for the local network. LAN computers will

assume this domain name when they get an address from the router's built in DHCP

server. So, for example, if you enter

mynetwork.net

here, and you have a LAN side

laptop with a name of

chris

, that laptop will be known as

chris.mynetwork.net

. Note,

however, the entered domain name can be overridden by the one obtained from the

router's upstream DHCP server.

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DNS Relay

When DNS Relay is enabled, the router plays the role of a DNS server. DNS requests

sent to the router are forwarded to the ISP's DNS server. This provides a constant DNS

address that LAN computers can use, even when the router obtains a different DNS

server address from the ISP upon re-establishing the WAN connection. You should

disable DNS relay if you implement a LAN-side DNS server as a virtual server.

Primary DNS Server, Secondary DNS Server

Enter the IP addresses of the DNS Servers. Leave the field for the secondary server

empty if not used.

RIP (Routing Information Protocol)

Used to broadcast routing information among routers.

Enable RIP

Enable RIP if required by the ISP, if the LAN has multiple routers, or if the LAN has auto-

IP devices.

RIP Operating mode

This router supports both version 2 and version 1 of the RIP specification.

V1.

Use if none of the routers supports Version 2.

V2 Broadcast.

Use if some routers are capable of Version 2, but some are only capable

of Version 1.

V2 Multicast.

Use if this is the only router on the LAN or if all the routers support Version

2.

Router Metric

The additional cost of routing a packet through this router. The normal value for a simple

network is 1. This metric is added to routes learned from other routers; it is not added to

static or system routes.

Act as default router

Make this router the preferred destination for packets that are not otherwise destined.

Accept WAN updates

For security, disable this option unless required by the ISP.

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RIP Password

RIP Version 2 supports the use of a password to limit access to routers through the RIP

protocol. If the ISP or other LAN router requires a RIP password, enter the password

here.

DHCP

DHCP Server Settings

DHCP stands for Dynamic Host Configuration Protocol. The DHCP section is where you

configure the built-in DHCP Server to assign IP addresses to the computers and other

devices on your local area network (LAN).

Enable DHCP Server

Once your router is properly configured and this option is enabled, the DHCP Server will

manage the IP addresses and other network configuration information for computers and

other devices connected to your Local Area Network. There is no need for you to do this

yourself.

The computers (and other devices) connected to your LAN also need to have their

TCP/IP configuration set to "DHCP" or "Obtain an IP address automatically".

When you set

Enable DHCP Server

, the following options are displayed.

DHCP IP Address Range

These two IP values (

from

and

to

) define a range of IP addresses that the DHCP Server

uses when assigning addresses to computers and devices on your Local Area Network.

Any addresses that are outside of this range are not managed by the DHCP Server;

these could, therefore, be used for manually configured devices or devices that cannot

use DHCP to obtain network address details automatically.

It is possible for a computer or device that is manually configured to have an address that

does reside within this range. In this case the address should be reserved (see

DHCP

Reservation

below), so that the DHCP Server knows that this specific address can only

be used by a specific computer or device.

Your router, by default, has a static IP address of 192.168.0.1. This means that

addresses 192.168.0.2 to 192.168.0.254 can be made available for allocation by the

DHCP Server.

Example:

Your router uses 192.168.0.1 for the IP address. You've assigned a computer that you

want to designate as a Web server with a static IP address of 192.168.0.3. You've

assigned another computer that you want to designate as an FTP server with a static IP

address of 192.168.0.4. Therefore the starting IP address for your DHCP IP address

range needs to be 192.168.0.5 or greater.

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Example:

Suppose you configure the DHCP Server to manage addresses From 192.168.0.100 To

192.168.0.199. This means that 192.168.0.3 to 192.168.0.99 and 192.168.0.200 to

192.168.0.254 are NOT managed by the DHCP Server. Computers or devices that use

addresses from these ranges are to be manually configured. Suppose you have a web

server computer that has a manually configured address of 192.168.0.100. Because this

falls within the "managed range" be sure to create a reservation for this address and

match it to the relevant computer (see

Static DHCP Client

below).

DHCP Lease Time

The amount of time that a computer may have an IP address before it is required to

renew the lease. The lease functions just as a lease on an apartment would. The initial

lease designates the amount of time before the lease expires. If the tenant wishes to

retain the address when the lease is expired then a new lease is established. If the lease

expires and the address is no longer needed than another tenant may use the address.

Always Broadcast

If all the computers on the LAN successfully obtain their IP addresses from the router's

DHCP server as expected, this option can remain disabled. However, if one of the

computers on the LAN fails to obtain an IP address from the router's DHCP server, it may

have an old DHCP client that incorrectly turns off the broadcast flag of DHCP packets.

Enabling this option will cause the router to always broadcast its responses to all clients,

thereby working around the problem, at the cost of increased broadcast traffic on the

LAN.

NetBIOS Advertisement

Check this box to allow the DHCP Server to offer NetBIOS configuration settings to the

LAN hosts. NetBIOS allows LAN hosts to discover all other computers within the network,

e.g. within Network Neighbourhood.

Learn NetBIOS information from WAN

If NetBIOS advertisement is swicthed on, switching this setting on causes WINS

information to be learned from the WAN side, if available. Turn this setting off to configure

manually.

Primary WINS Server IP address

Configure the IP address of the preferred WINS server. WINS Servers store information

regarding network hosts, allowing hosts to 'register' themselves as well as discover other

available hosts, e.g. for use in Network Neighbourhood. This setting has no effect if the

'Learn NetBIOS information from WAN' is activated.

Secondary WINS Server IP address

Configure the IP address of the backup WINS server, if any. This setting has no effect if

the 'Learn NetBIOS information from WAN' is activated.

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NetBIOS Scope

This is an advanced setting and is normally left blank. This allows the configuration of a

NetBIOS 'domain' name under which network hosts operate. This setting has no effect if

the 'Learn NetBIOS information from WAN' is activated.

NetBIOS Registration mode

Indicates how network hosts are to perform NetBIOS name registration and discovery.

H-Node, this indicates a Hybrid-State of operation. First WINS servers are tried, if any,

followed by local network broadcast. This is generally the preferred mode if you have

configured WINS servers.

M-Node (default), this indicates a Mixed-Mode of operation. First Broadcast operation is

performed to register hosts and discover other hosts, if broadcast operation fails, WINS

servers are tried, if any. This mode favours broadcast operation which may be preferred if

WINS servers are reachable by a slow network link and the majority of network services

such as servers and printers are local to the LAN.

P-Node, this indicates to use WINS servers ONLY. This setting is useful to force all

NetBIOS operation to the configured WINS servers. You must have configured at least

the primary WINS server IP to point to a working WINS server.

B-Node, this indicates to use local network broadcast ONLY. This setting is useful where

there are no WINS servers available, however, it is preferred you try M-Node operation

first.

This setting has no effect if the 'Learn NetBIOS information from WAN' is activated.

Number of Dynamic DHCP Clients

In this section you can see what LAN devices are currently leasing IP addresses.

Revoke

The

Revoke

option is available for the situation in which the lease table becomes full or

nearly full, you need to recover space in the table for new entries, and you know that

some of the currently allocated leases are no longer needed. Clicking

Revoke

cancels

the lease for a specific LAN device and frees an entry in the lease table. Do this only if

the device no longer needs the leased IP address, because, for example, it has been

removed from the network.

Reserve

The

Reserve

option converts this dynamic IP allocation into a DHCP Reservation and

adds the corresponding entry to the DHCP Reservations List.