Exam 70-462, Tracert And Traceroute in Linux

Although tracert and traceroute on LINXU are both traced by route, the data types of the two detection methods and probes are different. Exam 70-462 exam, By default, traceroute sends a UDP datagram to a port (greater than 30000) of the destination address, Exam 70-462 exam, and tracert sends an ICMP request to the destination address to echo the packet.

Conclusion: The reason for the above problem is probably that the destination server or router has released the ICMP package. Exam 70-462 exam, However, the UDP packets are filtered, or the ports are restricted

Tracert is a route-tracking utility that determines the path taken by an IP datagram to access a destination. Exam 70-462 exam, The Tracert command to use the IP Time to Live (TTL) field and ICMP error messages to determine the route from one host to another on the network.

Working principle and process:
Exam 70-462 exam, The Tracert Diagnostics determines the route to take the destination by sending an Internet Control Message Protocol (ICMP) response packet with a different IP Time to Live (TTL) value to the destination. Exam 70-462 exam, Each router on the path is required to decrement the TTL on the packet before forwarding the packet at least. Exam 70-462 exam, When the TTL on the packet is reduced to 0, Exam 70-462 exam,  the router should send a message “ICMP has timed out” back to the source system.

Tracert first sends a response packet with a TTL of 1, Exam 70-462 exam, and increments the TTL by 1 in each subsequent transmission until the target response or TTL reaches a maximum value to determine the route. Exam 70-462 exam, The route is determined by checking the “ICMP has timed out” message sent back by the intermediate router. Exam 70-462 exam, Some routers drop TTL expired packets without asking, Exam 70-462 exam, which is not visible in the Tracert utility.

The Tracert command prints out the list of near-end router interfaces in the path that returns the “ICMP Timed Out” message. Exam 70-462 exam, If you use the -d option, Exam 70-462 exam, the Tracert utility does not query DNS on every IP address.