Host A pings interface S0/0 on router 3. What is the TTL value for that ping?
A.
252
B.
253
C.
254
D.
255
Explanation:
From the CCNA ICND2 Exam book: “Routers decrement the TTL by 1 every time they forward a
packet; if a router decrements the TTL to 0, it throws away the packet. This prevents packets from
rotating forever.” I want to make it clear that before the router forwards a packet, the TTL is still
remain the same. For example in the topology above, pings to S0/1 and S0/0 of Router 2 have the
same TTL.
The picture below shows TTL values for each interface of each router and for Host B. Notice that
Host A initializes ICMP packet with a TTL of 255:
B. 253
B. 253 (since it is not yet been passed the router3)
B
253
At first TTl will be 255
1 decrement with router 1 and another 1 decrement with router 2 n as it comes before Router 3