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Chapter 4

Content Filtering

This chapter describes how to use the content filtering features of the TA612V Broadband Voice

Adapter to protect your network. These features can be found by clicking on the Content Filtering

heading in the Main Menu of the browser interface.

The TA612V Broadband Voice Adapter provides you with web content filtering options, plus

browsing activity reporting and instant alerts via e-mail. Parents and network administrators can

establish restricted access policies based web addresses and web address keywords. You can also

block Internet access by applications and services, such as chat or games.

Blocking Access to Internet Sites

The TA612V adapter allows you to restrict access based on web addresses and web address

keywords. Up to 255 entries are supported in the Keyword list. The Block Sites menu is below:

Figure 4-1:

Block Sites menu

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To enable keyword blocking, select either “Per Schedule” or “Always”, then click Apply. If you

want to block by schedule, be sure that a time period is specified in the Schedule menu.

To add a keyword or domain, type it in the Keyword box, click Add Keyword, then click Apply.

To delete a keyword or domain, select it from the list, click Delete Keyword, then click Apply.

Keyword application examples:

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If the keyword "XXX" is specified, the URL <http://www.badstuff.com/xxx.html> is blocked.

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If the keyword “.com” is specified, only websites with other domain suffixes (such as .edu or

.gov) can be viewed.

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If you wish to block all Internet browsing access during a scheduled period, enter the keyword

“.” and set the schedule in the Schedule menu.

To specify a Trusted User, enter that computer’s IP address in the Trusted User box and click

Apply. You may specify one Trusted User, which is a computer that will be exempt from blocking

and logging. Since the Trusted User will be identified by an IP address, you should configure that

computer with a fixed IP address.

Blocking Access to Internet Services

The TA612V adapter allows you to block the use of certain Internet services by computers on your

network. This is called services blocking or port filtering. The Block Services menu is shown

below:

Figure 4-2:

Block Services menu

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Services are functions performed by server computers at the request of client computers. For

example, web servers serve web pages, time servers serve time and date information, and game

hosts serve data about other players’ moves. When a computer on your network sends a request for

service to a server computer on the Internet, the requested service is identified by a service or port

number. This number appears as the destination port number in the transmitted IP packets. For

example, a packet that is sent with destination port number 80 is an HTTP (web server) request.

To specify a service for blocking, click Add. The Add Services menu will appear, as shown below:

Figure 4-3:

Add Services menu

From the Service Type list, select the application or service to be allowed or blocked. The list

already displays several common services, but you are not limited to these choices. To add any

additional services or applications that do not already appear, select User Defined.

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Configuring a User Defined Service

To define a service, first you must determine which port number or range of numbers is used by

the application. The service numbers for many common protocols are defined by the Internet

Engineering Task Force (IETF) and published in RFC1700, “Assigned Numbers.” Service

numbers for other applications are typically chosen from the range 1024 to 65535 by the authors of

the application. This information can usually be determined by contacting the publisher of the

application or from user groups of newsgroups.

Enter the Starting Port and Ending Port numbers. If the application uses a single port number, enter

that number in both boxes.

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If you know that the application uses either TCP or UDP, select the appropriate protocol. If you are

not sure, select Both.

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Configuring Services Blocking by IP Address Range

Under “Filter Services For”, you can block the specified service for a single computer, a range of

computers (having consecutive IP addresses), or all computers on your network.

Configuring E-Mail Alert and Web Access Log Notifications

In order to receive logs and alerts by email, you must provide your email information in the E-Mail

menu, shown below:

Figure 4-4:

Email menu

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Turn e-mail notification on

Check this box if you wish to receive e-mail logs and alerts from the router.

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Send to this e-mail address

Enter the e-mail address to which logs and alerts are sent. This e-mail address will also be used

as the From address. If you leave this box blank, log and alert messages will not be sent via

e-mail.

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Your outgoing mail server

Enter the name of your ISP’s outgoing (SMTP) mail server (such as mail.myISP.com). You

may be able to find this information in the configuration menu of your e-mail program. If you

leave this box blank, log and alert messages will not be sent via e-mail.

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My Mail Server Requires Authentication

Select this checkbox and enter the user name and password for this email account, as required.

You can specify that logs are automatically sent to the specified e-mail address with these options:

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Send alert immediately

Check this box if you would like immediate notification of attempted access to a blocked site.

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Send logs according to this schedule

Specifies how often to send the logs: None, Hourly, Daily, Weekly, or When Full.

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Day for sending log. Specifies which day of the week to send the log. Relevant when the

log is sent weekly or daily.

–

Time for sending log. Specifies the time of day to send the log. Relevant when the log is

sent daily or weekly.

If the Weekly, Daily or Hourly option is selected and the log fills up before the specified

period, the log is automatically e-mailed to the specified e-mail address. After the log is sent,

the log is cleared from the router’s memory. If the router cannot e-mail the log file, the log

buffer may fill up. In this case, the router overwrites the log and discards its contents. If you

don't want logs sent, select None from the list in the Send Logs According To This Schedule

area. When you turn on e-mail notification and choose None in the Send Logs According to

this Schedule list, the alert is sent but not the log.

The TA612V adapter uses the Network Time Protocol (NTP) to obtain the current time and date

from one of several Network Time Servers on the Internet. In order to localize the time for your

log entries, you must specify your Time Zone:

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Time Zone. Select your local time zone. This setting will be used for the blocking schedule

and for time-stamping log entries.

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Daylight Savings Time. Check this box to automatically adjust for daylight savings time.