Manage the MTU Size, MTU Concepts, Application | NETGEAR D6100

AC1200 WiFi DSL Modem Router—Essentials Edition Model D6100

Manage the MTU Size

The maximum transmission unit (MTU) is the largest data packet a network device transmits.

MTU Concepts

When one network device communicates across the Internet with another, the data packets travel through many devices along the way. If a device in the data path uses a lower MTU setting than the other devices, the data packets must be split or “fragmented” to accommodate the device with the smallest MTU.

The best MTU setting for NETGEAR equipment is often the default value. In some situations, changing the value fixes one problem but causes another.

Leave the MTU unchanged unless one of these situations occurs:

•You experience problems connecting to your ISP or other Internet service, and the technical support of either the ISP or NETGEAR recommends changing the MTU setting. These web-based applications might require an MTU change:

-A secure website that does not open or displays only part of a web page

-Yahoo email

-MSN portal

-America Online’s DSL service

•You use VPN and experience severe performance problems.

•You used a program to optimize MTU for performance reasons and now you are experiencing connectivity or performance problems.

If you suspect an MTU problem, a common solution is to change the MTU to 1400. If you are willing to experiment, you can gradually reduce the MTU from the maximum value of 1500 until the problem goes away. The following table describes common MTU sizes and applications.

Table 3. Common MTU sizes

MTU	Application

1500	The largest Ethernet packet size. This setting is typical for connections that do not use PPPoE
	or VPN and is the default value for NETGEAR modem routers, adapters, and switches.

1492	Used in PPPoE environments.

1472	Maximum size to use for pinging. (Larger packets are fragmented.)

1468	Used in some DHCP environments.

1460	Usable by AOL if you do not send or receive large email attachments, for example.

1436	Used in PPTP environments or with VPN.

1400	Maximum size for AOL DSL.

Manage the Internet Settings Manually

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NETGEAR D6100 user manual Manage the MTU Size, MTU Concepts, Application

Contents

AC1200 WiFi DSL Modem Router- Essentials Edition Compliance SupportTrademarks Contents Manage the WiFi Network Settings Manage the WAN and LAN Network Settings Manage Firewall Rules, Port Forwarding, and Port Triggering Appendix a Supplemental Information Router Unpack Your Modem Router Your package contains the following items Front Panel with LEDs Modem router displays status LEDs on the front panel Power LED turns solid green LED descriptions Back Panel with Ports, Buttons, and Connector Modem router back panel Right Side Panel with WPS and WiFi On/Off Buttons Button Icon Description Bottom Panel Product Label Modem router product label Install and Access the Modem Router and Its Network Position Your Modem Router Types of Logins Wired ConnectionWiFi Connection Before You Connect to the Modem Router Netgear genie Automatic Setup Utility Set Up Your Modem Router for DSL Service DSL Service  To connect your modem router to a DSL service Modem router cabling for DSL service Install and Access the Modem Router and Its Network Install and Access the Modem Router and Its Network Install and Access the Modem Router and Its Network Install and Access the Modem Router and Its Network Install and Access the Modem Router and Its Network Set Up Your Modem Router for Cable or Fiber Service  To connect your modem router to a cable or fiber service Modem router cabling for cable or fiber service Install and Access the Modem Router and Its Network Install and Access the Modem Router and Its Network Install and Access the Modem Router and Its Network Install and Access the Modem Router and Its Network Read Troubleshoot the Internet Connection on  To log in to the modem router Change the Language  To change the language Select Advanced Administration Set Password  To set up password recovery Set Up Password RecoveryLet the Modem Router Automatically Update Its Firmware Select the Enable Password Recovery check box Access the Modem Router with the Netgear genie App  To use the genie app to access the modem router Install and Access the Modem Router and Its Network Manage the Internet Settings Manually  To use the Setup Wizard Use the Internet Setup Wizard After Initial SetupSelect Advanced Setup Wizard Manage the Internet Settings Manually Manage the Internet Settings Manually Manage the Internet Settings Manually Manage the Internet Settings Manually Manually Set Up the Internet Connection Specify an Internet Connection Without a Login Field Description Internet IP Address Router MAC Address Domain Name Server DNS AddressNAT Network Address Translation Manage the Internet Settings Manually Or Manually Connect Domain Name Server DNS Address From the Encapsulation menu, select PPPoE PPP over Ethernet Enter the settings as described in the following table Internet IP Address From the Encapsulation menu, select PPPoA PPP over ATM Enter the settings as described in the following table IPv6 Internet Connections and IPv6 Addresses Specify an IPv6 Internet ConnectionField Description Internet IP Address Set Up and IPv6 Connection Through Auto Detect From the Internet Connection Type menu, select Auto Detect Set Up and IPv6 Connection Through Auto Config From the Internet Connection Type menu, select Auto Config Manage the Internet Settings Manually Set Up an IPv6 6to4 Tunnel Connection From the Internet Connection Type menu, select 6to4 Tunnel Manage the Internet Settings Manually Set Up an IPv6 Pass-Through Connection  To set up an IPv6 pass-through Internet connection  To set up a fixed IPv6 Internet connection Set Up an IPv6 Fixed ConnectionFrom the Internet Connection Type menu, select Fixed Manage the Internet Settings Manually  To set up an IPv6 Internet connection with a Dhcp server Set Up an IPv6 Dhcp ConnectionFrom the Internet Connection Type menu, select Dhcp Manage the Internet Settings Manually  To set up an IPv6 PPPoE Internet connection Set Up an IPv6 PPPoE ConnectionFrom the Internet Connection Type menu, select PPPoE Manage the Internet Settings Manually MTU Concepts Manage the MTU SizeApplication Change the MTU Size Manage the WiFi Network Settings View or Change the Basic WiFi Settings  To view or change the basic WiFi settings Manage the WiFi Network Settings Wireless Network 2.4GHz b/g/n Field Description Region Selection Wireless Network 5GHz 802.11a/n/ac Field Description Security Options To 173 Mbps Configure WPA/WPA2 Enterprise WiFi Security  To configure WPA/WPA2 enterprise security Manage the WiFi Network Settings Configure WEP Legacy WiFi Security  To configure WEP security Use WPS to Add a Device to the WiFi Network Use WPS with the Push Button Method Select Advanced WPS Wizard Use WPS with the PIN Method Manage the WiFi Network Settings  To set up a guest network Select Guest Network To access My Local Network check box Field Description Wireless Network 2.4GHz b/g/nEnable Ssid Broadcast check box Security Options Profile Field Description Wireless Network 5GHz a/n/ac Ssid Broadcast check box Use the WiFi On/Off Button Control the WiFi RadiosEnable or Disable the WiFi Radios  To enable or disable the WiFi radios Select Advanced Advanced Setup Wireless Settings Set Up a WiFi Schedule  To set up the WiFi schedule Manage the WiFi Network Settings Manage the WPS Settings  To manage WPS Settings Manage Advanced WiFi Features  To manage advanced WiFi features Preamble Mode  To set up the modem router as an AP Use the Modem Router as a WiFi Access PointTransmit Power Control menu Select Advanced Advanced Setup Wireless Access Point Control Access to the Internet  To set up parental controls Set Up Parental ControlsSelect Parental Controls Control Access to the Internet Enable and Manage Network Access Control Allow or Block Access to Your NetworkClick the Take me to the status screen button  To set up network access control Manage Network Access Control Lists  To add or remove devices that are allowed Control Access to the Internet 103 Add or Remove Devices from the Blocked List  To add or remove devices that are blocked Use Keywords to Block Internet Sites Set Up Blocking To set up keyword and domain blocking Select Advanced Security Block Sites Control Access to the Internet 106  To remove a keyword or domain from the blocked list Remove a Keyword or Domain from the Blocked ListRemove All Keywords and Domains from the Blocked List  To remove all keywords and domains from the blocked list Specify a Trusted Computer  To specify a trusted device  To set up a schedule for blocking Select Advanced Security Schedule Set Up Security Event Email Notifications  To set up email notifications Send Alert Immediately Field Description Send alerts and logs through e-mailSend logs according to this schedule Optimize Performance Select Advanced Setup QoS Setup Optimize Traffic with QoS Select the Turn Internet Access QoS On check box Manage Default and Custom QoS RulesAdd a Custom QoS Rule for a Service or Application  To add a QoS rule for a service or application From the Applications menu, select Add a new application Optimize Performance 116  To add a QoS rule for a device Add a Custom QoS Rule for a DeviceField Description Specified Port Range Optimize Performance 118 Change a QoS Rule or Change the Priority for a Rule  To change a QoS rule Remove a QoS Rule  To remove a QoS rule Remove All QoS Rules Manage Uplink Bandwidth Control To remove all QoS rules Click the OK button Basic Home screen displays Improve Network Connections with Universal Plug and Play  To manage Universal Plug and Play Manage Wi-Fi Multimedia Quality of Service  To disable WMM QoS Settings  To view or change the DSL setup Manage the Adsl SettingsSelect Advanced Setup Adsl Settings Change the WAN Connection Preference  To change the WAN connection preference Manage the WAN Security Settings  To change the default WAN security settings Set Up a Default DMZ Server  To set up a default DMZ server Manage Igmp Proxying and VPN Pass-Through  To change the default NAT filtering settings Enable and Configure a VlanManage NAT Filtering Select Advanced Setup WAN Setup  To enable and configure the Vlan To change the default SIP ALG setting Manage the SIP Application-Level Gateway Select Advanced Advanced Setup Dynamic DNS Set Up a New Dynamic DNS AccountManage Dynamic DNS  To set up Dynamic DNS if you already created an account Specify a DNS Account That You Already Created Manage the Modem Router’s LAN IP Address Settings Select the Use a Dynamic DNS Service check box  To change the LAN IP address settings Select Advanced Setup LAN Setup Manage the Router Information Protocol Settings  To manage the RIP settings Reserve a LAN IP address Manage Reserved LAN IP Addresses To reserve an IP address  To change a reserved IP address entry Change a Reserved IP AddressRemove a Reserved IP Address Entry  To remove a reserved IP address entry Manage the Dhcp Server Address Pool Change the Modem Router’s Device Name To change the modem router’s device name Manage the WAN and LAN Network Settings 141  To disable the built-in Dhcp server Disable the Built-In Dhcp ServerClear the Use Router as Dhcp Server check box Set Up a Static Route Set Up and Manage Custom Static Routes To set up a static route Manage the WAN and LAN Network Settings 144  To change a static route Change a Static RouteRemove a Static Route  To remove a static route Manage the WAN and LAN Network Settings 146 Manage the Modem Router Monitor the Traffic Check for New Firmware and Update the Modem Router Update the Firmware of the Modem Router To check for new firmware and update your modem router Manually Upload New Firmware and Update the Modem Router D6100-V1.0.0.340.0.34.img Restore the Settings Manage the Configuration File of the Modem RouterBack Up the Settings  To back up the modem router’s configuration settings Recover the admin Password  To recover your password Use the Reset Button Return the Modem Router to Its Factory Default Settings To reset the modem router to factory default settings Erase the Settings  To erase the settings View the Status and Statistics of the Modem Router Select Advanced Advanced Home Manage the Modem Router and Monitor the Traffic 156 Field Description Router Information Wireless Settings 2.4GHz Internet Port Wireless Settings 5.0GHz Guest Network 2.4GHz View the Traffic Statistics Guest Network 5.0GHz Field or Column Description Adsl Link View or Change a TCP/IP Internet Connection  To view or change the TCP/IP Internet connection status Manage the Modem Router and Monitor the Traffic 162 View or Change a PPPoE or PPPoA Internet Connection View or Change a Pptp or L2TP Internet Connection View the Logs Select Advanced Administration LogsManage the Activity Log and Syslog  To manage which activities are logged and view the log Manage the Modem Router and Monitor the Traffic 166 Specify a Syslog Server Specify Which Activities Are Logged To manage which activities are logged View Devices Currently on the Network  To display the wired and WiFi devicesSelect Attached Devices Select Advanced Advanced Setup Traffic Meter Start the Traffic Meter Without Traffic Volume RestrictionsMonitor and Meter Internet Traffic View the Traffic Statistics and Traffic Status Restrict Internet Traffic by Volume  To record and restrict the Internet traffic by volume Select the Traffic volume control by radio button Restrict Internet Traffic by Connection Time  To record and restrict the Internet traffic by time Unblock the Traffic Meter After the Traffic Limit Is Reached  To unblock the traffic meter Select Advanced Advanced Setup Remote Management  To set up remote managementManage the Modem Router Remotely Select the Turn Remote Management On check box  To configure the modem router as a DSL modem only Configure the Modem Router as a DSL Modem Only To use remote access From the Device Mode menu, select Modem Modem Only Manage Firewall Rules, Port Forwarding, and Port Triggering  To add an outbound firewall rule Add an Outbound Firewall RuleSelect Advanced Security Firewall Rules Allow always Block alwaysBlock by schedule, otherwise allow Allow by schedule, otherwise block Change an Outbound Firewall Rule  To change an outbound firewall rule Change the Priority of an Outbound Firewall Rule  To change the priority of an outbound firewall rule Disable or Enable an Outbound Firewall Rule  To enable or disable an outbound firewall rule Remove an Outbound Firewall Rule  To remove an outbound firewall rule Select Advanced Security Firewall Rules Starting Port field  To change a custom service or application  To remove a custom service or application Following figure shows two entries in the Service Table AC1200 WiFi DSL Modem Router-Essentials Edition Model D6100 AC1200 WiFi DSL Modem Router-Essentials Edition Model D6100 Click the Add Custom Service button Change a Port Forwarding Rule  To change a port forwarding rule Remove a Port Forwarding Rule  To remove a port forwarding rule Application Example Make a Local Web Server Public  To make a local web server public Manage Port Triggering for Services and Applications How the Modem Router Implements the Port Forwarding Rule Add a Port Triggering Rule  To add a port triggering rule  To change a port triggering rule Change a Port Triggering RuleInbound Connection AC1200 WiFi DSL Modem Router-Essentials Edition Model D6100 Remove a Port Triggering Rule  To remove a port triggering rule Specify the Time-Out Period for Port Triggering Disable Port Triggering To disable port triggering  To specify the time-out for port triggering Clear the Disable Port Triggering check box Application Example Port Triggering for Internet Relay Chat AC1200 WiFi DSL Modem Router-Essentials Edition Model D6100 Diagnostics and Troubleshooting Perform a DNS Lookup Perform DiagnosticsPing an IP Address  To ping an IP address Display the Routing Table  To display the routing table Reboot the Modem Router from the Web Management Interface Quick Tips for TroubleshootingProblem Possible Solution Troubleshoot with the LEDs Bottom Panel Product Label on Power LED Is Off Power LED Remains Solid AmberWiFi LED Is Off You Cannot Log In to the Modem Router Troubleshoot the Internet Connection Troubleshoot the DSL Link Obtain an Internet IP Address Internet LED Is Off To check the Internet IP address Troubleshoot PPPoE or PPPoA  To verify that your PPPoE or PPPoA connection is working Troubleshoot Internet Browsing Troubleshoot the WiFi Connectivity Changes Are Not Saved Test the LAN Path to Your Modem Router Troubleshoot Your Network Using the Ping Utility To ping the modem router from a Windows computer Test the Path from Your Computer to a Remote Device Supplemental Information Main WiFi network Factory SettingsFeature Default Behavior Router login Internet connection Guest WiFi network Feature Default BehaviorGeneral WiFi settings Technical Specifications Feature Description Supplemental Information 221