User's Manual
Table Of Contents
- Reference Manual for the Model FWAG114 Cable/ DSL Wireless ProSafe Firewall
- Contents
- About This Manual
- Chapter 1 Introduction
- Chapter 2 Connecting the Firewall to the Internet
- Chapter 3 Wireless Configuration
- Chapter 4 Firewall Protection and Content Filtering
- Chapter 5 Maintenance
- Chapter 6 Advanced Configuration
- Chapter 7 Troubleshooting
- Appendix A Technical Specifications
- Appendix B Network, Routing, Firewall, and Basics
- Appendix C Preparing Your Network
- Appendix D Wireless Networking Basics
- Glossary
- Index
- About This Manual
- Chapter 1 Introduction
- Chapter 2 Connecting the Firewall to the Internet
- Chapter 3 Wireless Configuration
- Observe Performance, Placement, and Range Guidelines
- Implement Appropriate Wireless Security
- Understanding Wireless Settings
- Chapter 4 Firewall Protection and Content Filtering
- Firewall Protection and Content Filtering Overview
- Block Sites
- Using Rules to Block or Allow Specific Kinds of Traffic
- Services
- Using a Schedule to Block or Allow Specific Traffic
- Getting E-Mail Notifications of Event Logs and Alerts
- Viewing Logs of Web Access or Attempted Web Access
- Configuring E-Mail Alert and Web Access Log Notifications
- Chapter 5 Maintenance
- Chapter 6 Advanced Configuration
- Chapter 7 Troubleshooting
- Appendix A Technical Specifications
- Appendix B Network, Routing, Firewall, and Basics
- Appendix C Preparing Your Network
- Appendix D Wireless Networking Basics
- Glossary
- Index
Reference Manual for the Model FWAG114 Cable/DSL Wireless ProSafe Firewall
B-6 Network, Routing, Firewall, and Basics
Although the preceding example uses the entire third octet for a subnet address, note that you are
not restricted to octet boundaries in subnetting. To create more network numbers, you need only
shift some bits from the host address to the network address. For instance, to partition a Class C
network number (192.68.135.0) into two, you shift one bit from the host address to the network
address. The new netmask (or subnet mask) is 255.255.255.128. The first subnet has network
number 192.68.135.0 with hosts 192.68.135.1 to 129.68.135.126, and the second subnet has
network number 192.68.135.128 with hosts 192.68.135.129 to 192.68.135.254.
The following table lists the additional subnet mask bits in dotted-decimal notation. To use the
table, write down the original class netmask and replace the 0 value octets with the dotted-decimal
value of the additional subnet bits. For example, to partition your Class C network with subnet
mask 255.255.255.0 into 16 subnets (4 bits), the new subnet mask becomes 255.255.255.240.
The following table displays several common netmask values in both the dotted-decimal and the
masklength formats.
Note: The number 192.68.135.127 is not assigned because it is the broadcast address of the first subnet.
The number 192.68.135.128 is not assigned because it is the network address of the second subnet.
Table 8. Netmask Notation Translation Table for One Octet
Number of Bits Dotted-Decimal Value
1128
2192
3224
4240
5248
6252
7254
8255
Table 9. Netmask Formats
Dotted-Decimal Masklength
255.0.0.0 /8
255.255.0.0 /16