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Chapter 3 IP Firewall Service 57
Practical Examples
The IP filters you create work together to provide security for your network. The
examples that follow show how to use filters to achieve some specific goals.
Block Access to Internet Users
This section shows you, as an example, how to allow users on your subnet access to
your server’s Web service, but deny access to the general public on the Internet:
To do this:
1 In Server Admin, choose Firewall from the Computers & Services list.
2 Click Settings.
3 Select the General tab.
4 Select the Any address group.
5 Make sure that Web Service is disabled in the right pane.
6 Click the Add button to create an address range.
7 Name the address group.
8 Add the local network address range.
This is done by using an example address from the network with its network mask in
CIDR notation. For example, if a user has an address of 192.168.1.20 and the network
mask is 255.255.255.0, then enter 192.168.1.20/24.
9 Click OK.
10 Select your newly created address group.
11 Select “Web Service” in the right pane to enable web access.
12 Click Save.
Block Junk Mail
This section shows you, as an example, how to reject email from a junk mail sender
with an IP address of 17.128.100.0 and accept all other Internet email:
LL2351.Book Page 57 Monday, September 8, 2003 2:47 PM