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D6200 WiFi DSL Modem Router

Change the MTU Size

The maximum transmission unit (MTU) is the largest data packet a network device transmits.

When one network device communicates across the Internet with another, the data packets

travel through many devices along the way. If any device in the data path has a lower MTU

setting than the other devices, the data packets have to be split or “fragmented” to

accommodate the device with the smallest MTU.

The best MTU setting for NETGEAR equipment is often just the default value, and changing

the value might fix one problem but cause another. Leave the MTU unchanged unless one of

these situations occurs:

•

You have problems connecting to your ISP or other Internet service, and the technical

support of either the ISP or NETGEAR recommends changing the MTU setting. These

web-based applications might require an MTU change:

-

A secure website that does not open, or displays only part of a web page

-

Yahoo email

-

MSN portal

-

America Online’s DSL service

•

You use VPN and have severe performance problems.

•

You used a program to optimize MTU for performance reasons, and now you have

connectivity or performance problems.

Note:

An incorrect MTU setting can cause Internet communication

problems such as the inability to access certain websites, frames

within websites, secure login pages, or FTP or POP servers.

If you suspect an MTU problem, a common solution is to change the MTU to 1400. If you are

willing to experiment, you can gradually reduce the MTU from the maximum value of 1500

until the problem goes away. The following table describes common MTU sizes and

applications.

Table 8.

Common MTU sizes

MTU

Application

1500

The largest Ethernet packet size. This is the typical setting for non-PPPoE, non-VPN

connections, and is the default value for NETGEAR WiFi DSL modem routers, adapters,

and switches.

1492

Used in PPPoE environments.

1472

Maximum size to use for pinging. (Larger packets are fragmented.)

1468

Used in some DHCP environments.

1460

Usable by AOL if you do not have large email attachments, for example.

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D6200 WiFi DSL Modem Router



To change the MTU size:

1.

Select

ADVANCED > Setup > WAN Setup

.

2.

In the MTU Size field, enter a new size from 64 through 1500.

3.

Click

Apply

.

LAN Setup

The LAN Setup screen allows configuration of LAN IP services such as Dynamic Host

Configuration Protocol (DHCP) and Routing Information Protocol (RIP).

The WiFi DSL modem router is shipped preconfigured to use private IP addresses on the

LAN side and to act as a DHCP server. The WiFi DSL modem router’s default LAN IP

configuration is:

•

LAN IP address.

192.168.0.1

•

Subnet mask.

255.255.255.0

These addresses are part of the designated private address range for use in private networks

and should be suitable for most applications. If your network requires a different IP

addressing scheme, make changes in the LAN Setup screen.

Note:

If you change the LAN IP address of the WiFi DSL modem router

while connected through the browser, you are disconnected. You

have to open a new connection to the new IP address and log in

again.

1436

Used in PPTP environments or with VPN.

1400

Maximum size for AOL DSL.

576

Typical value to connect to dial-up ISPs.

Table 8.

Common MTU sizes

(continued)

MTU

Application

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D6200 WiFi DSL Modem Router



To change the LAN settings:

1.

Select

ADVANCED > Setup > LAN Setup

.

2.

Enter the settings that you want to customize.

These settings are described in the following section,

LAN Setup Screen Settings

.

3.

Click

Apply

.

LAN Setup Screen Settings

You can configure the settings described in the following sections:

LAN TCP/IP Setup

•

IP Address

. The LAN IP address of the WiFi DSL modem router.

•

IP Subnet Mask

. The LAN subnet mask of the WiFi DSL modem router. Combined with

the IP address, the IP subnet mask allows a device to know which other addresses are

local to it, and which have to be reached through a gateway or WiFi DSL modem router.

•

RIP Direction

. Router Information Protocol (RIP) allows a router to exchange routing

information with other routers. This setting controls how the router sends and receives

RIP packets. Both is the default setting. With the Both or Out Only setting, the router

broadcasts its routing table periodically. With the Both or In Only setting, the router

incorporates the RIP information that it receives.

•

RIP Version

. This setting controls the format and the broadcasting method of the RIP

packets that the WiFi DSL modem router sends. It recognizes both formats when

receiving. By default, the RIP function is disabled.

-

RIP-1

is universally supported. It is adequate for most networks, unless you have an

unusual network setup.

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D6200 WiFi DSL Modem Router

-

RIP-2

carries more information. Both RIP-2B and RIP-2M send the routing data in

RIP-2 format. RIP-2B uses subnet broadcasting. RIP-2M uses multicasting.

Use Router as DHCP Server

This check box is selected so that the WiFi DSL modem router functions as a Dynamic Host

Configuration Protocol (DHCP) server.

•

Starting IP Address

. Specify the start of the range for the pool of IP addresses in the

same subnet as the WiFi DSL modem router.

•

Ending IP Address

. Specify the end of the range for the pool of IP addresses in the

same subnet as the WiFi DSL modem router.

For more information, see

Use the WiFi DSL Modem Router as a DHCP Server

on page 54.

Address Reservation

When you specify a reserved IP address for a computer on the LAN, that computer receives

the same IP address each time it accesses the WiFi DSL modem router’s DHCP server.

Assign reserved IP addresses to servers that require permanent IP settings. For more

information, see

Address Reservation

on page 55.

Use the WiFi DSL Modem Router as a DHCP Server

By default, the WiFi DSL modem router functions as a DHCP server, allowing it to assign IP,

DNS server, and default gateway addresses to all computers connected to the WiFi DSL

modem router’s LAN. The assigned default gateway address is the LAN address of the WiFi

DSL modem router. The WiFi DSL modem router assigns IP addresses to the attached

computers from a pool of addresses specified in this screen. Each pool address is tested

before it is assigned to avoid duplicate addresses on the LAN. For most applications, the

default DHCP and TCP/IP settings of the WiFi DSL modem router are satisfactory.

You can specify the pool of IP addresses that are assigned by setting the starting IP address

and ending IP address. These addresses should be part of the same IP address subnet as

the WiFi DSL modem router’s LAN IP address. Using the default addressing scheme, you

should define a range between 192.168.0.2 and 192.168.0.254, although you might want to

save part of the range for devices with fixed addresses.

The WiFi DSL modem router delivers the following parameters to any LAN device that

requests DHCP:

•

An IP address from the range you defined

•

Subnet mask

•

Gateway IP address (the WiFi DSL modem router’s LAN IP address)

•

Primary DNS server (if you entered a primary DNS address in the Internet Setup screen;

otherwise, the WiFi DSL modem router’s LAN IP address)

•

Secondary DNS server (if you entered a secondary DNS address in the Internet Setup

screen)

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To use another device on your network as the DHCP server, or to manually configure the

network settings of all of your computers, clear the

Use Router as DHCP Server

check box

and click

Apply

. Otherwise, leave this check box selected. If this service is not enabled and

no other DHCP server is available on your network, you need to set your computers’ IP

addresses manually or they are not able to access the WiFi DSL modem router.

Address Reservation

When you specify a reserved IP address for a computer on the LAN, that computer always

receives the same IP address each time it accesses the WiFi DSL modem router’s DHCP

server. Reserved IP addresses should be assigned to computers or servers that require

permanent IP settings.



To reserve an IP address:

1.

Select

ADVANCED > Setup > LAN Setup

.

2.

In the Address Reservation section of the screen, click the

Add

button.

3.

In the IP Address field, type the IP address to assign to the computer or server. (Choose an

IP address from the WiFi DSL modem router’s LAN subnet, such as 192.168.0.x.)

4.

Type the MAC address of the computer or server.

Tip:

If the computer is already on your network, you can copy its MAC

address from the Attached Devices screen and paste it here.

5.

Click

Apply

.

The reserved address is not assigned until the next time the computer contacts the WiFi

DSL modem router’s DHCP server. Reboot the computer, or access its IP configuration

and force a DHCP release and renew.



To edit or delete a reserved address entry:

1.

Select the radio button next to the reserved address you want to edit or delete.

2.

Click one of the following buttons:

Edit

or

Delete

.