The current firmware allows the maximum transmission unit to be changed if needed. If you are having a problem sending or receiving email, or connecting to secure sites such as eBay, banking sites, and Hotmail, we suggest lowering the MTU in increments of ten (Ex. 1492, 1482, 1472, etc).
What is my MTU? - To find the proper MTU Size, you?ll have to do a special ping of the destination you?re trying to go to. A destination could be another computer, or a URL.
Step 1 Click on Start and then click Run.
Step 2 Windows 95, 98, and ME users type in command (Windows NT, 2000, and XP users type in cmd) and press Enter (or click OK).
Step 3 Once the window opens, you?ll need to do a special ping. Use the following syntax:
ping [url] [-f] [-l] [MTU value]
Example: ping yahoo.com -f -l 1472
You should start at 1472 and work your way down by 10 each time. Once you get a reply, go up by 2 until you get a fragmented packet. Take that value and add 28 to the value to account for the various TCP/IP headers. For example, lets say that 1452 was the proper value, the actual MTU size would be 1480, which is the optimum for the network we?re working with (1452+28=1480).
Once you find your MTU, you can now configure your router with the proper MTU size.
Note: AOL DSL+ users must use MTU of 1400.
To change the MTU rate follow the steps below:
For the DI-514, DI-524, DI-604, DI-614+, DI-624, DI-754, DI-764, DI-774, and DI-784:
Step 1 Open your browser, enter the IP address of your router (192.168.0.1) and click OK.
Step 2 Enter your username (admin) and password (blank by default). Click OK to enter the web configuration page for the device.
Step 3 Click on the Home tab and go to the WAN tab.
Step 4 The default MTU is 1500, to change this enter the number in the MTU field and click the Apply button to save your settings.
Step 5 Test your email. If changing the MTU does not resolve the problem, continue changing the MTU in increments of ten.
Note: If you have the European version of the DI-604, this procedure will not work.
If you do not have an MTU option, please upgrade your firmware.