Computer Science 881
                             Quiz 2           Name____________________

1. The reason that the "ping" program must be run with root privileges
   is that:

   a. The getprotobyname() function     b. Creation of a socket of
      fails since ICMP is a protected      type SOCK_RAW fails on Unix
      protocol.                            systems unless the caller is
                                           running as root.

   c. The gethostbyname() function      d. All of the above
      is priviledged.

2. The standard "ping" program:

   a. Sends a UDP packet and            b. Sends an ICMP packet and
      receives an ICMP reply.              receives a UDP reply

   c. Sends a UDP packet and            d. Sends an ICMP packet and
      receives a UDP reply                 receives an ICMP reply

3. When a "ping" packet travels across the network

   a. An ICMP echo reply is returned    b. An ICMP echo reply is returned
      by every router through which        only by the destination host.
      it passes.

   c. no ICMP echo replies are generated
      at all because ping uses UDP.

4. The IP record route option can record only 9 hops.  This
   restriction is caused by:

   a. an unfortunate design decision    b. A global limitation on the
      by the writer of "ping"              size of ANY IP header.

   c. a global limitation on the        d. The fact that there aren't
      size of ANY IP packet.               enough bits allocated for
                                           specifying the length of
                                           IP header options.

5. The "traceroute" program sends out

   a. an ICMP message                   b. a UDP datagram

   c. a raw IP packet associated
      with no transport protocol
      at all.

6. The "traceroute" program expects to receive

   a. an ICMP message                   b. a UDP datagram

   c. a raw IP packet associated
      with no transport protocol
      at all.

7. Suppose a path between two hosts is "N" hops long. Then
   it takes N packet transmissions to send a SINGLE packet
   from one host to the other.

   a. How many total packet transmissions are required by the
      original traceroute program. (Assume that only ONE
      packet is issued by the sending host for EACH value of TTL
      and that there are no retries.







   b. How many total packet transmissions are required by the
      proposed new traceroute facility. (Assume the packet issued
      by the sending host travels travels only one way (i.e.
      the receiver DOES not reply to it.).




8.  One advantage of cited by the authors of the new RFC 1393 traceroute
    was that two new and potentially useful items of information would be
    returned to the sender in the replies. What were they?

    a -


    b -



9. In the RFC 1393 traceroute, replies are returned to the sender
   using

    a. an ICMP message                   b. a UDP datagram

    c. a raw IP packet associated
       with no transport protocol
       at all.

10. For the standard "ping" and the standard "traceroute" programs:

    a. Both use a single socket         b. Ping uses 2 sockets and
                                           traceroute 1

    c. Traceroute uses 2 sockets        d. Both use 2 sockets.
       and ping 1.


11. What is the diffence between loose and strict source routing?





12. Suppose a loose source routed message specifies three intermediate
    routers:

     S -------> R1 -------->   R2 ------->  R3  -------->  D

    What will be the contents (in correct order) of the source
    route options during the transmission from R1 to R2.