What is the TTL when pinging?

TTL means “time to live”. It is a value on an ICMP packet that prevents that packet from propagating back and forth between hosts ad infinitum. Each router that touches the packet decrements the TTL. If the TTL ever reaches zero, the packet is discarded.

What is TTL 64 in ping?

64 is the number of hops that the packet can travel before it is dropped. Hard to reach hosts that are across many hops of the Internet benefit from a larger TTL on packets. In multicast protocols 64 is used to restrict the packet to the same physical region.

How do I use TTL in ping?

To ping with a custom TTL:

1. Open a command prompt.
2. Type ping 8.8. 8.8 and press Enter.
3. Observe the results. The ping request should be successful.
4. Type ping -i 1 8.8. 8.8 and press Enter.
5. Observe the results.
6. Type ping -i 2 8.8.
7. Observe the results.
8. Close the command prompt to complete this activity.

What is TTL 255 in ping?

1.1) the ttl is 255. since the default original ttl value by ping is 255, as it reaches a router (hop), it decrements the ttl value by 1 and becomes 254. Let’s look at what the RFC has to say: When a router forwards a packet, it MUST reduce the TTL by at least one.

How to calculate the TTL value of a ping?

With the initial TTL value is 128 with the end of the TTL value can be calculated are the number of hop from computer to computer of origin purposes. Each time through a packet PING ip address then its TTL value would be reduced one. So if the TTL value reaches zero, packet will discard PING / PING drop and the results show: TTL expired in transit

How to Ping a server, Ping port of a router?

If you want to resolve the hostname of a target IP address , use ( -a) ping command option. if possible it will resolve the hostname of a specified IP address. -f ping cmd option is used if you want to prevent routers from the fragmentation of ICMP Echo Requests between source and the target.

How does TTL work on a UDP packet?

It builds a “dummy” UDP packet and sets TTL to 1 and then sends it. The first router that receives the packet decrements TTL, sees that TTL is now zero, drops the packet and (hopefully) builds an ICMP Time Exceeded (type 11, code 0) to return to the sender.

What’s the target IP address for extended Ping?

With extended ping, you get the option to specify the source address of the ping packet, as shown here. Router A> enable Router A# ping Protocol [ip]: Target IP address: 192.168.40.1 !— The address to ping.