How to Check Optimium MTU Size Value Of Your Network

MTU (maximum transmission unit) tells the maximum possible size of the packets send from your network. It is important to set the optimum MTU size to achieve the maximum throughput through your network. As the packet size increases, we can expect more efficiency with a downside of increasing lag time. So it is important to have the correct Maximum Transmission Unit size set for your network. Different medias have different MTU value. For example 1500 is the optimum value for EthernetV2 but 1492 is the optimum MTU value for PPPoE. There is a ping command to check whether your current Maximum Transmission Unit value is the optimum size for your network.

Ping Test to Determine Correct MTU Size of a Network

As we know it is important to have the correct  size set. We can determine if the the current value set is the correct  by doing a simple ping test.
  1. Open Command Prompt

  2. Type ping [Destination Address]–f –l [Testing MTU Value]

    Eg: ping www.corenetworkz.com -f -l 1472

  3. If you receive proper replies from the destination, the size you have tested is the standard/optimum value for your network.

  4. If you have received an error message Packet needs to be fragmented but DF set, the MTU size you have tested is too big for your network.
    Test your current MTU size

    To learn more about this message, visit the link below.
    Packet needs to be fragmented but DF set
The above image tells the result of ping test to determine the optimum MTU value for the network I am using. 1480 is too big for my network and that is why here I received the error message instead of replies from destination. Similarly you can change the TTL value fo ping packets send from your computer.
How to Change Default TTL Value Set On Ping Packets

If you find the current Maximum Transmission Unit value set for your network is not the optimum value, you must change it immediately to get the maximum throughput for your network. You can change it on your Modem or Router which is used on your network. Similarly you can change the size of ping request packets send from your computer.
How to Change Default Size of Ping Echo Request On Your Computer

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