D-Link DIR-685 User Manual page 142

Section 8 - Troubleshooting
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.
To change the MTU rate on your router follow the steps below:
• Open your browser, enter the IP address of your router (192.168.0.1) and click OK.
• Enter your username (admin) and password (blank by default). Click OK to enter the web configuration
page for the device.
• Click on Setup and then click Manual Configure.
• To change the MTU enter the number in the MTU field and click Save Settings to save your settings.
• Test your e-mail. If changing the MTU does not resolve the problem, continue changing the MTU in
increments of ten.
4. What can I do if the DIR-685 locks up or stops responding?
If the LCD touchpad panel ever becomes unresponsive, or if the router itself is malfunctioning, you may need to reset
the device. The DIR-685 can be reset by unplugging the power adapter from the wall for a few seconds. Plug it back
in and wait a few moments for the router to restart.
Note: There is no on/off button on the router. The reset button on the back of the router is used to restore the router
settings to factory defaults.
D-Link DIR-685 User Manual 137