SAVI Source Address Validation Improvements

Source Address Validation Improvements (SAVI) is a set of techniques and protocols designed to enhance the security and reliability of IP networks by preventing the use of forged or spoofed source IP addresses. The primary goal of SAVI is to ensure that the source IP address of a packet is legitimate and corresponds to the actual network entity that sent the packet. This helps prevent various types of network attacks and provides a means to trace the origin of malicious activities.

SAVI aims to address the limitations of traditional IP packet filtering mechanisms, such as access control lists (ACLs) and firewall rules, which are often ineffective in preventing IP address spoofing. By implementing SAVI, network operators can enforce stronger verification of source IP addresses and enhance the trustworthiness of network traffic.

The key components and techniques employed in SAVI include:

1. Binding Table: SAVI relies on a binding table that maintains the mapping between IP addresses and their associated network entities. The binding table stores the legitimate associations between IP addresses and their corresponding MAC addresses or other unique identifiers.
2. Source Address Validation: When a packet arrives at a SAVI-enabled network device, such as a switch or a router, the source IP address is checked against the binding table. If the source IP address is not found in the binding table, it is considered unauthorized or spoofed.
3. Dynamic Binding: SAVI allows for the dynamic creation and maintenance of bindings in the binding table. This enables new IP addresses to be associated with the appropriate MAC addresses or identifiers when devices join the network. Dynamic binding can be achieved using mechanisms such as DHCP snooping, Neighbor Discovery Protocol (NDP) snooping, or Secure Neighbor Discovery (SEND) protocol.
4. Packet Filtering and Forwarding: SAVI-enabled devices can be configured to drop or quarantine packets with unauthorized or spoofed source IP addresses. This prevents the delivery of malicious or unauthorized traffic to the network. Depending on the implementation, SAVI can also provide additional options for handling non-compliant traffic, such as rate limiting or redirection to a separate quarantine network.
5. Logging and Reporting: SAVI implementations typically include logging and reporting mechanisms to track and record the activities related to source IP address validation. This allows network administrators to analyze the traffic patterns, identify potential security breaches, and investigate any unauthorized or spoofed IP address usage.
6. Integration with Existing Network Infrastructure: SAVI can be integrated into existing network infrastructure by deploying SAVI-enabled devices, such as switches, routers, or firewalls, at strategic points in the network topology. SAVI can also work in conjunction with other network security mechanisms, such as Intrusion Detection Systems (IDS) or Intrusion Prevention Systems (IPS), to provide a comprehensive security solution.

SAVI has been standardized by the Internet Engineering Task Force (IETF) in the form of Request for Comments (RFCs) that define the protocols and mechanisms for source address validation. Notable RFCs related to SAVI include RFC 7039 ("Source Address Validation Improvement (SAVI) Framework") and RFC 7513 ("Source Address Validation Improvement (SAVI) Solution for DHCP").

By implementing SAVI, network operators can significantly reduce the risk of IP address spoofing and enhance the security and trustworthiness of their IP networks. SAVI serves as an important tool in preventing various network attacks, such as distributed denial-of-service (DDoS) attacks, IP address hijacking, or IP address forgery, and contributes to overall network security and stability.