Packet filtering

Packet filtering deletes packets before they are delivered to the destination computer. Packet filtering can delete packets based on the following:

• The address the data is coming from.
• The address the data is going to.
• The session and application ports being used to transfer the data.
• The data contained within the packet.

Typically there are two types of packet filtering: stateful and stateless. Stateful packet filters remember the state of connections at the network and session layers by recording the established session information that passes through the filter gateway. The filter then uses that information to discriminate valid return packets from invalid connection attempts. Stateless packet filters do not retain information about connections in use; instead, they make determinations packet-by-packet based only on the information contained within the packet. Firewalls that employ packet filtering will work with Crystal Enterprise.