Changing Mtu Size To Improve Network Performance; Setting Dns Server Addresses; Controlling Management Access To The Dfl-500 - D-Link DFL-500 User Manual

gateway IP address fields. These fields are colored grey to indicate that the addresses have not been
assigned manually.

Changing MTU size to improve network performance

To improve the performance of your internet connection, you can adjust the maximum transmission unit (MTU)
of the packets that the DFL-500 transmits from its external interface. Ideally, you want this MTU to be the
same as the smallest MTU of all the networks between your machine and the Internet. If your packets are
larger, they get broken up or fragmented, which slows down transmission speeds.
Trial and error is the only sure way of finding the optimal MTU, but there are some guidelines that can help.
For example, the MTU of many PPP connections is 576, so if you connect to the Internet via PPP or PPPoE,
you might want to set the MTU of the DFL-500 to 576. DSL modems may also have small MTU sizes. Most
ethernet networks have an MTU of 1500.
If you connect to your ISP using DHCP to obtain an IP address for the external interface, you cannot set the MTU
below 576 bytes due to DHCP communication standards.
To change the MTU size of the packets leaving the external interface:
•
Go to System > Network > IP Address .
•
Click Fragment outgoing packets greater than MTU.
•
Set the MTU size.
Set the maximum packet size in the range of 68 to 1500 bytes. The default MTU size is 1500. Experiment by
lowering the MTU to find an MTU size for best network performance.

Setting DNS server addresses

Several functions of the DFL-500, including sending alert emails and URL blocking, use DNS.
To set the DNS server addresses using the web-based manager:
•
Go to System > Config > DNS .
•
Change the primary and secondary DNS server addresses as required.

Controlling management access to the DFL-500

Use the options on the Management Access page to control access to the DFL-500 web-based manager and
the CLI through the Internal and External (from the Internet) interfaces. Administrators access the web-based
manager using HTTPS. Administrators access the CLI remotely using SSH.
•
Go to System > Network > Access .
•
Check or uncheck the following parameters for each interface:
HTTPS To allow secure connections to the web-based manager.
PING
If you want the DFL-500 to respond to pings. Use this setting to verify your installation and for testing.
SSH
If you want to allow secure SSH connections to the CLI.
Checking HTTPS or SSH for the external interface allows remote administration of the DFL-500 from any
location on the Internet.
•
Click Apply.
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