User's Manual
Table Of Contents
- AC1900 Cable Modem Voice Router
- 1. Hardware Overview
- 2. Connect to the Network and Access the Modem Router
- 3. Specify Your Internet Settings
- 4. Control Access to the Internet
- 5. Share USB Devices Attached to the Modem Router
- USB Storage Device Requirements
- Connect a USB Storage Device to the Modem Router
- Access a USB Drive Connected to the Modem Router From a Windows Computer
- Map a USB Device to a Windows Network Drive
- Access a USB Storage Device That Is Connected to the Modem Router From a Mac
- Control Access to the USB Storage Device
- Use FTP Within the Network
- View Network Folders on a USB Storage Device
- Add a Network Folder on a USB Storage Device
- Edit a Network Folder on a USB Storage Device
- Approve USB Devices
- Access the USB Storage Device Through the Internet
- Safely Remove a USB Storage Device
- 6. Share a USB Printer
- 7. Voice Telephone Lines
- 8. Specify Network Settings
- View or Change WAN Settings
- Set Up a Default DMZ Server
- Manually Configure LAN Switch Ports
- Change the Modem Router’s Device Name
- Change the LAN TCP/IP Settings
- Specify the IP Addresses That the Modem Router Assigns
- Disable the DHCP Server Feature in the Modem Router
- Manage LAN IP Addresses
- Improve Network Connections With Universal Plug-N-Play
- Use the WPS Wizard for WiFi Connections
- Specify Basic WiFi Settings
- Change the WiFi Security Option
- Set Up a Guest Network
- Control the WiFi Radios
- Specify WPS Settings
- 9. Manage Your Network
- Change the admin Password
- View Modem Router Status
- View the Battery Status
- View and Manage Logs of Modem Router Activity
- View Event Logs
- Run the Ping Utility
- Run the Traceroute Utility
- Monitor Internet Traffic
- View Devices Currently on the Network
- Manage the Modem Router Configuration File
- View Wireless Access Points in Your Area
- View or Change the Modem Router Wireless Channel
- Dynamic DNS
- Remote Management
- 10. Specify Internet Port Settings
- 11. Troubleshooting
- A. Supplemental Information
Specify Internet Port Settings
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AC1900 Cable Modem Voice Router
If you are not sure, select TCP/UDP.
10. In the Service Type fields, enter the starting and ending ports.
11. Enter the inbound connection port information in the Starting Port and Ending Port fields.
12. Click the Apply button.
The service is now in the Portmap table. You must enable port triggering before the
modem router uses port triggering for the service that you added.
Application Example: Port Triggering for Internet Relay Chat
Some application servers, such as FTP and IRC servers, send replies to multiple port
numbers. Using port triggering, you can tell the modem router to open more incoming ports
when a particular outgoing port starts a session.
An example is Internet Relay Chat (IRC). Your computer connects to an IRC server at
destination port 6667. The IRC server not only responds to your originating source port, but
also sends an “identify” message to your computer on port 113. Using port triggering, you can
tell the modem router, “When you initiate a session with destination port 6667, you must also
allow incoming traffic on port 113 to reach the originating computer.” The following sequence
shows the effects of this port triggering rule you defined:
1. You open an IRC client program to start a chat session on your computer.
2. Your IRC client composes a request message to an IRC server using a destination port
number of 6667, the standard port number for an IRC server process. Your computer then
sends this request message to your modem router.
3. Your modem router creates an entry in its internal session table describing this
communication session between your computer and the IRC server. Your modem router
stores the original information, performs Network Address Translation (NAT) on the source
address and port, and sends this request message through the Internet to the IRC server.
4. Noting your port triggering rule and observing the destination port number of 6667, your
modem router creates another session entry to send any incoming port 113 traffic to your
computer.
5. The IRC server sends a return message to your modem router using the NAT-assigned
source port (for example, port 33333) as the destination port. The IRC server also sends an
“identify” message to your modem router with destination port 113.
6. When your modem router receives the incoming message to destination port 33333, it
checks its session table to see if a session is active for port number 33333. Finding an active
session, the modem router restores the original address information replaced by NAT and
sends this reply message to your computer.
7. When your modem router receives the incoming message to destination port 113, it checks
its session table and finds an active session for port 113 associated with your computer. The
modem router replaces the message’s destination IP address with your computer’s IP
address and forwards the message to your computer.
8. When you finish your chat session, your modem router eventually senses a period of
inactivity in the communications. The modem router then removes the session information
from its session table, and incoming traffic is no longer accepted on port numbers 33333 or
113.