| 27.1 | Nothing changes; all the systems are neighbors, so a strict source route is identical to a loose source route. |
| 27.2 | We would place an EOL (a byte of 0) at the end of the buffer. |
| 27.3 | Since ping creates a raw socket (Chapter 28), it receives the complete IP header, including any IP options, on every datagram it reads with recvfrom. |
| 27.4 | rlogind is invoked by inetd (Section 13.5), so descriptor 0 is the socket to the client. |
| 27.5 | The problem is that the fifth argument to setsockopt is the pointer to the length, instead of the length. This bug was probably fixed when ANSI C prototypes were first used. As it turns out, the bug is harmless, because as we mentioned, to clear the IP_OPTIONS socket option, we can specify either a null pointer as the fourth argument or a fifth argument (the length) of 0 (p.269 of TCPv2). |