On Networks N300RM User Manual - Manual (Page 50)

Security Settings
50
N300 WiFi ADSL2+ Modem Router (N300RM)
- Time . Specify the time of day to send the log. This is relevant when the log is sent
daily or weekly.
Note: If the Weekly, Daily, or Hourly option is selected and the log fills up
before the specified period, the log is automatically emailed to the
specified email address. After the log is sent, it is cleared from the
modem router’s memory. If the modem router cannot email the log
file, the log buffer might fill up. In this case, the modem router
overwrites the log and discards its contents.
Port Forwarding and Port Triggering
By default, the modem router blocks inbound traffic from the Internet to your computers
except replies to your outbound traffic. You might need to create exceptions to this rule for
these purposes:
• To allow remote computers on the Internet to access a server on your local network.
•
To allow certain applications and games to work correctly when your router does not
recognize their replies.
Your modem router provides two features for creating these exceptions: port forwarding and
port triggering. The next sections provide background information to help you understand
how port forwarding and port triggering work, and the differences between the two.
Remote Computer Access Basics
When a computer on your network needs to access a computer on the Internet, your
computer sends your modem router a message containing the source and destination
address and process information. Before forwarding your message to the remote computer,
your modem router has to modify the source information and create and track the
communication session so that replies can be routed back to your computer.
Here is an example of normal outbound traffic and the resulting inbound responses:
1. You open a browser, and your operating system assigns port number 5678 to this
browser session.
2. You type http://www.example.com into the URL field, and your computer creates a web
page request message with the following address and port information. The request
message is sent to your modem router.
Source address . Your computer’s IP address.
Source port number . 5678, which is the browser session.
Destination address . The IP address of www.example.com, which your computer finds
by asking a DNS server.