Filter

Filter Example

A filter for blocking the web service

- Configuration

Before configuring a filter, you need to know the following information:

1. The outbound packet type (protocol & port number)
2. The source IP address

Generally, the outbound packets for Web service could be as following:

a. HTTP packet, TCP (06) protocol with port number 80
b. DNS packet, TCP (06) protocol with port number 53 or
c. DNS packet, UDP (17) protocol with port number 53

For all workstation on the LAN, the source IP address will be 0.0.0.0. Otherwise, you have to enter an IP Address for the workstation you want to block. See the procedure for configuring this filter below.

- Create a filter set in Menu 21, e.g., set 1
- Create three filter rules in Menu 21.1.1, Menu 21.1.2, Menu 21.1.3

- Rule 1- block the HTTP packet, TCP (06) protocol with port number 80
- Rule 2- block the DNS packet, TCP (06) protocol with port number 53
- Rule 3- block the DNS packet, UDP (17) protocol with port number 53

- Apply the filter set in menu 4

1. Create a filter set in Menu 21

`Menu 21 - Filter Set Configuration`

`Filter Filter`
`Set # Comments Set # Comments`
`------ ----------------- ------ -----------------`
`1 Web Request 7 _______________`
`2 8 _______________`
`3 9 _______________`
`4 10 _______________`
`5 11 _______________`
`6 _______________ 12 _______________`

`Enter Filter Set Number to Configure= 1`

`Edit Comments=`

`Press ENTER to Confirm or ESC to Cancel:`

2. Rule one for (a). http packet, TCP(06)/Port number 80

`Menu 21.1.1 - TCP/IP Filter Rule`

`Filter #: 1,1`
`Filter Type= TCP/IP Filter Rule`
`Active= Yes`
`IP Protocol= 6 IP Source Route= No`
`Destination: IP Addr= 0.0.0.0`
`IP Mask= 0.0.0.0`
`Port #= 80`
`Port # Comp= Equal`
`Source: IP Addr= 0.0.0.0`
`IP Mask= 0.0.0.0`
`Port #=`
`Port # Comp= None`
`TCP Estab= No`
`More= No Log= None`
`Action Matched= Drop`
`Action Not Matched= Check Next Rule`

`Press ENTER to Confirm or ESC to Cancel:`

3.Rule 2 for (b).DNS request, TCP(06)/Port number 53

`Menu 21.1.2 - TCP/IP Filter Rule`

`Filter #: 1,2`
`Filter Type= TCP/IP Filter Rule`
`Active= Yes`
`IP Protocol= 6 IP Source Route= No`
`Destination: IP Addr= 0.0.0.0`
`IP Mask= 0.0.0.0`
`Port #= 53`
`Port # Comp= Equal`
`Source: IP Addr= 0.0.0.0`
`IP Mask= 0.0.0.0`
`Port #=`
`Port # Comp= None`
`TCP Estab= No`
`More= No Log= None`
`Action Matched= Drop`
`Action Not Matched= Check Next Rule`

`Press ENTER to Confirm or ESC to Cancel:`

4. Rule 3 for (c). DNS packet UDP(17)/Port number 53

`Menu 21.1.2 - TCP/IP Filter Rule`

`Filter #: 1,2`
`Filter Type= TCP/IP Filter Rule`
`Active= Yes`
`IP Protocol= 17 IP Source Route= No`
`Destination: IP Addr= 0.0.0.0`
`IP Mask= 0.0.0.0`
`Port #= 53`
`Port # Comp= Equal`
`Source: IP Addr= 0.0.0.0`
`IP Mask= 0.0.0.0`
`Port #=`
`Port # Comp= None`
`TCP Estab= No`
`More= No Log= None`
`Action Matched= Drop`
`Action Not Matched= Forward`

`Press ENTER to Confirm or ESC to Cancel:`

5. After the three rules are completed, you will see the rule summary in Menu 21.

`Menu 21.1 - Filter Rules Summary`

`# A Type Filter Rules M m n`
`- - ---- -------------------------------------- - - -`
`1 Y IP Pr=6, SA=0.0.0.0, DA=0.0.0.0, DP=80 N D N`
`2 Y IP Pr=6, SA=0.0.0.0, DA=0.0.0.0, DP=53 N D N`
`3 Y IP Pr=17, SA=0.0.0.0, DA=0.0.0.0,DP=53 N D F`

6. Apply the filter set to the 'Output Protocol Filter Set' in the remote node setup

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