The Maximum Transmission Unit (MTU) feature of your Linksys router is an advanced configuration that allows you to determine the largest data size permitted on your connection. Generally, if your MTU is too large for the connection, your computer will experience packet loss or dropping internet connection.
This article will help you determine and set up the correct MTU size. To know how, follow the steps below:
Determining the correct MTU size
To determine the correct MTU size for your network, you’ll have to do a specific ping test on the destination you’re trying to go to like using another computer or a web address.
For Windows® computers, use the following command for the ping test: ping [url / local server or IP Address] –f –l xxxx
- For example: “ping www.yahoo.com –f –l 1472”
For Mac® computers, use the following command for the ping test: ping [url / local server or IP Address] –d –s xxxx
- For example: “ping www.yahoo.com –d –s 1472”
In determining your network’s MTU size, you’ll need to know the following information to understand the concept of using certain commands through the command prompt.
- Ping: a command to determine the connectivity between your computer and a particular address (within the Local network or the internet).
- URL or local address: the web address or the IP address of the server you’re trying to check for speed connectivity.
- -f: a command to make sure that when you ping a certain address, it will not fragment the packet sent or received.
- -l: a command commonly known as a packet size switch. This is the best command to help you determine the best MTU size for your network.
- xxxx: the packet size (value) which you will test. You can start from 1472 until you can reach the exact packet size which will not result to the prompt “Packet needs to be fragmented but DF set.” You may decrease the value by 10.
Here are the results that you may get after doing the ping test:
- Four replies received: This means that the packet size entered is either within or the actual MTU size used within your network.
- Destination net unreachable: This means that there was no path or route to the destination or the address.
- Request Timed Out: This means that within the default wait time period (1 second), there was no response.
- Packet needs to be fragmented but DF set: This means that the packet size you entered is too high for your MTU value.
- Bad parameter –f: This means that you have typed the command incorrectly.
To do the ping test, follow the steps below according to the operating system that you are using:
NOTE: The MTU size of the Linksys routers is 1500.