Advantages of Packet Filtering Firewalls
Packet-filtering firewalls have two main advantages:
® They can process packets at very fast speeds.
® They easily can match on most fields in Layer 3 packets and Layer 4 segment headers, providing a lot of flexibility in implementing security policies.
Because packet-filtering firewalls examine only Layer 3 and/or Layer 4 information, many routing products support this type of filtering; this includes Cisco routers with the use of standard and extended ACLs. Depending on the router model that you purchase, you can scale your filtering to very high speeds.
Because routers are typically at the perimeter of your network, providing WAN and MAN access, you can use packet filtering to provide an additional layer of security. These routers commonly are called perimeter or boundary routers, and they were shown previously inFiqure 2-6. Even with simple Layers 3 and 4 filtering, packet-filtering firewalls can provide protection against many types of attacks, including certain types of denial-of-service (DoS) attacks, and can filter out unnecessary, unwanted, and undesirable traffic. This allows an internal firewall to deal with other types of threats and attacks that the packet-filtering firewall cannot detect or deal with.
Continue reading here: Figure 28 Packet Filtering Firewall Example Initiating Connections
Was this article helpful?