How To Fix the MTU on a Computer

First of all, what is an MTU? MTU, or maximum transmission unit, refers to the data byte size that can be transmitted via the Internet over a period of time. In simplest terms, the higher the MTU rate, the more efficient your computer is at sending packets of data over the Internet. Do know, however, that lower MTU may be better for particular situations. This is because ISP and Internet routers will fragment or “chop up” data packets beyond their programmed limits, and if your MTU is larger than your router’s limits, the data will have to be fragmented and then reassembled once it reaches its destination. This process of fragmentation-reassembly is not optimal and may result in lost data packets.

Normally, the way to fix or adjust the MTU settings is via the router hardware, and not the computer itself. However, there are some ways that you could try out if you want to try fixing the MTU on your computer itself. Here are some tips to help you out:

Do a ping test. The MTU Dos ping test will help you determine the optimal MTU settings for your computer. First, you have to pull up the DOS settings on your computer; do this by following these steps:

First, go to the start button at the lower left portion of your screen. Click on the button that says, “Run”.

Next, type down “cmd” if your computer runs on Windows 2000 or XP, or “command” if your computer runs on Windows 98/ ME. Type this command down at the Open field. Hit the enter key, and you would see the DOS prompt.

At the DOS prompt, type down –f –l 1492 and press enter.

The results you see will indicate whether the packets your computer sends through the Internet needs to be fragmented. If you find that your data does need to be fragmented, lower the packet size in increments of 10, until you see results that tell you that your data doesn’t need to be fragmented anymore.

Download DRCTP. Another way to adjust your MTU rate is through DRCTP. DRCTP is a type of freeware that is available for downloading through sites such as Once you have downloaded this software, you will  be able to more easily adjust your computer MTU rates.

Once you start the DRCTP program, you will see a pop-up box with a field on its lowest portion that says, “Adapter Settings”. Choose the network adapter that you use. Then, go to the field opposite this field, the one that says, “MTU”. Type down the numerical value of the MTU that your computer needs to work at maximum efficiency. Know that the typical value for MTU without the data getting fragmented is at 1500, although the maximum recommended MTU for Internet PPPoE implementations is at 1492.

Click on the “OK” button, and you may have to restart your computer in order for these settings to work.

There you have it! These are some steps you can try out in order to fix the MTU on your computer. Good luck, and hope this helped you out!


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