We said that almost all fields in an IPv6 header and all extension headers are available to the application through socket options or ancillary data. What information in an IPv6 datagram is not available to an application?
What happens in Figure 28.40 if for some reason the client stops reading from its Unix domain connection to the icmpd daemon and lots of ICMP errors arrive for the client? What is the easiest solution?
If we specify the subnet-directed broadcast address to our ping program, it works. That is, a broadcast ICMP echo request is sent as a link-layer broadcast, even though we do not set the SO_BROADCAST socket option. Why?
