Table of Contents

Configuring and Testing PIX Firewall

Help Information
Abbreviating Commands
Configuring PIX Firewall
Connecting to the PIX Firewall
Starting a Console Session
Initially Configuring the PIX Firewall
Configuring with HTTP
Testing the Configuration
Adding to Your Configuration
Configuration Guidelines

Configuring and Testing PIX Firewall

You can configure PIX Firewall by entering commands on your console computer or terminal that are similar in context to those you use with Cisco routers.

Help Information

Help information is available by entering a question mark by itself for a listing of all commands, or with a command for command syntax. For example:

pixfirewall> int ?
usage: interface ethernet inside|outside 10baseT|100baseTX|auto

Abbreviating Commands

You can abbreviate most commands down to the fewest unique characters for a command; for example, you can enter write t to view the configuration instead of entering the full command write terminal, or you can enter en to start privileged mode and conf t to start configuration mode.

Configuring PIX Firewall

Configuring PIX Firewall consists of the following steps:

Step 1 Using the terminal or computer you connected to the console port during the PIX Firewall installation, connect to the firewall using a modem program such as Procomm.

Step 2 Once you get to the unprivileged command prompt, which should appear as pixfirewall>, proceed to configuration mode by first entering the enable command and then the config terminal command.

Step 3 Initially configure PIX Firewall using the commands described in the section that follows, "Initially Configuring the PIX Firewall."

Step 4 Exit configuration mode and save the configuration in flash memory with the write memory command.

Step 5 Change the default privileged mode password with the enable password command.

Step 6 Monitor the network interface traffic with the show interface command. If both interfaces show that packets are input and output, then the firewall is functioning. If not, ensure that the interface and route commands are specified correctly.

Step 7 Use the ping command to ensure that hosts on the inside and outside of the network are visible to the firewall.

Step 8 Test the network to ensure that you can ping between inside hosts, between outside hosts, and from an inside host to an outside host.

The configuration is now complete.

Connecting to the PIX Firewall

You can configure the PIX Firewall from the console or across the network with either Telnet or from a network browser such as Netscape Navigator. Before entering commands on the console, you need to have connected a workstation to the console port and started a modem program so that you can enter the initial configuration commands.

Before you can use Telnet, you need to enter the telnet command. Before you use a network browser, enter the http command. After you add these commands to the configuration, you can perform configuration remotely across the network.

Starting a Console Session

To start a console session, connect the console cable and start a terminal program such as Procomm. Set the baud rate to 9600, use 8 data bits, and no parity. Set the initialization string as follows so that the terminal program will communicate directly to the PIX Firewall instead of another modem:

ATE1V1X4Q0&C1&D2 S7=255 S0=0^M

Initially Configuring the PIX Firewall

Access configuration mode and enter the following commands to initially configure the firewall:

1. pixfirewall(config)# interface ethernet inside auto
   

2. pixfirewall(config)# interface ethernet outside auto
   

3. pixfirewall(config)# ip address inside ip_address netmask
   

4. pixfirewall(config)# ip address outside ip_address netmask
   

5. pixfirewall(config)# nat 1 0.0.0.0
   

6. pixfirewall(config)# global 1 ip_address_pool
   

7. pixfirewall(config)# route inside router_ip_address
   

8. pixfirewall(config)# route outside router_ip_address
   

9. pixfirewall(config)# ^z
   

10. pixfirewall# write memory
    

Alternatively, you can enter lines 1 through 4 and then complete your configuration with a network browser and the HTTP configuration feature of PIX Firewall. Refer to the next section "Configuring with HTTP." The use of the HTTP configuration feature also requires you to enter the http command as explained in "Configuring with HTTP."

Line 1 indicates that you are using an Intel 10/100 automatic speed sensing network interface card. This statement and that in line 2 set the interface speed. If your system contains 3Com Ethernet boards, replace auto with 10baseT. If your system contains Token-Ring cards, replace ethernet with token and auto with either 4mbps or 16mbps.

Lines 3 and 4 assign the IP addresses to the inside and outside network interface cards.

Line 5 disables network address translation until you can configure the system as required.

Line 6 assigns a pool of NIC-registered IP addresses for use by outbound connections. Enter a class address such as this example address of 192.168.42.0 to assign IP addresses 192.168.42.1 through 192.168.42.254.

Lines 7 and 8 let you assign default routes to the inside and outside network interfaces. If your system lets routers advertise default routes, these lines can be omitted.

Line 9 exits configuration mode and line 10 writes the current configuration to flash memory.

Configuring with HTTP

PIX Firewall provides a graphical user interface to help simplify configuration tasks. Once you have specified the network interface speed and IP addresses (as described in the last section), you need to enter two additional commands and you can then use a network browser, such as Netscape, to complete the configuration.

To access PIX Firewall from a network browser, enter these commands to specify an access password and your workstation's IP address and network mask:

pixfirewall(config)# passwd access_password
pixfirewall(config)# http ip_address network_mask

At your workstation, start a network browser. Then open a URL and specify the IP address of the PIX Firewall's inside IP address.

The network browser then prompts you for a user name and password as shown in Figure 3-1.

Figure 3-1 : HTML Management Interface User Name and Password Prompt

Always use admin for the user name and enter the password you specified with the passwd command.

The main configuration screen then appears as shown in Figure 3-2.

Figure 3-2 : HTML Management Interface Configuration Screen

Testing the Configuration