Which of the following commands is used to make traceroute wait 5 seconds for a response to a
packet?
A.
traceroute -w
B.
traceroute -T
C.
traceroute -q
D.
traceroute -r
Explanation:
The traceroute -w command is used to make traceroute wait 5 seconds (default) for a response to
a packet.
What is traceroute?
Traceroute is a route-tracing utility that displays the path an IP packet takes to reach its
destination.It uses Internet
Control Message Protocol (ICMP) echo packets to display the Fully Qualified Domain Name
(FQDN) and the IP address of each gateway along the route to the remote host. Traceroute sends
out a packet to the destination computer with the TTL field value of 1. When the first router in the
path receives the packet, it decrements the TTL value by
1. If the TTL value is zero, it discards the packet and sends a message back to the originating host
to inform it that the packet has been discarded. Traceroute records the IP address and DNS name
of that router, and sends another packet with a TTL value of
2. This packet goes through the first router, and then times out at the next router in the path. The
second router also sends an error message back to the originating host. Now, the process starts
once again and
traceroute continues to send data packets with incremented TTL values until a packet finally
reaches the target host, or until it decides that the host is unreachable. In the whole process,
traceroute also records the time taken for a round trip for each packet at each router.
Answer option B is incorrect. The traceroute -T command uses the TCP/SYN packets for probing.
Answer option C is incorrect. The traceroute -q command sets the number of probe packets per
hop.
The default value is 3.
Answer option D is incorrect. The traceroute -r command bypasses the normal routing tables and
sends the probe packet directly to a host on an attached network. If the host is not on a directlyattached network, an error is returned. This option can be used to ping a local host through an
interface that has no route through it.