| 29.2 | In our udpcksum program, common error replies are an ICMP "port unreachable" (the destination is not running a name server) or an ICMP "host unreachable." In either case, we need not wait for a timeout of our udp_read in Figure 29.10 because the ICMP error is essentially a reply to our DNS query. Modify the program to catch these ICMP errors. |
