Netgear AC1200 オーナーマニュアル

Click the Apply button.

Your change takes effect.

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 a 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. In some 
situations, changing the value fixes one problem but causes 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.

An incorrect MTU setting can cause Internet communication 

problems. For instance, you might not be able 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.  

1500

The largest Ethernet packet size. This setting is typical for connections that do not use 
PPPoE or VPN, and is the default value for NETGEAR routers, adapters, and switches.

1492

Used in PPPoE environments.