Answers

p. 513, 10.6

These RIP messages are all discarded, since no-one is listening at that port. However, an ICMP ``port unreachable'' is not generated, since the source address was broadcast (rule 5, p. 71).

p. 523, 28.3

Of course, the fact that the MTA makes several writes, one for each command, does not guarantee that each write is transmitted in a separate TCP segment, since, with Nagle on, several application writes can be combined into one segment. Hence the ``brain-dead'' implementations described in the answer are definitely wrong.