Which characteristic is associated with GRE packets?

The characteristic associated with GRE packets is that they use IP protocol 47. GRE, or Generic Routing Encapsulation, is a tunneling protocol used to encapsulate a variety of network Layer 3 protocols into virtual point-to-point links over an IP network. By convention, GRE is designated as protocol number 47 in the IP protocol suite, which allows routers to recognize GRE packets and process them accordingly.

This is significant because it helps in establishing and maintaining tunnels that enable the transport of data packets over an IP network while preserving the original packet's data. The identification of GRE packets by protocol number 47 ensures that routers and network devices can handle these encapsulated packets properly.

The other characteristics mentioned involve aspects not specific to GRE packets: for instance, while it is true that GRE tunneling can be used in conjunction with other protocols to enhance security and connectivity, GRE itself does not inherently provide authentication, nor does it mandate static routing exclusively. This underscores the importance of understanding the specific features and functions of GRE as a tunneling protocol in network configurations.