Filtering criteria in an IP packet

IP packets match IP filters based on a number of selection criteria. There are five primary pieces of information that are gathered from the IP packet, commonly referred to as a 5-tuple:

• Source address

  An IP packet can be filtered based on the source address located in the IP header of the packet.

• Destination address

  An IP packet can be filtered based on the destination address located in the IP header of the packet. For IPv6 packets that contain a type 0 or type 2 routing header, the stack performs IP filtering using the final destination address of the packet based on the routing header contents, not on the destination address in the IP header.

• Protocol

  An IP packet can be filtered based on the protocol in the IP header of the packet.

• Source port

  If the protocol in an IP packet is TCP or UDP, the packet can be filtered based on the source port in the TCP/UDP header of the data portion of the packet.

• Destination port

  If the protocol in an IP packet is TCP or UDP, the packet can be filtered based on the destination port in the TCP/UDP header of the data portion of the packet.