Difference between "request timed out" and "destination host unreachable"?
Few day before We are troubleshooting a networking problem in my office. We are getting RTO after some time on my RF link and after 4 or 5 RTO, getting Destination Host Unreachable for a long time. ISP saying that This problem creating due to Over Load on Link.
Before troubleshoot, I am learn about RTO and Destination Host Unreachable. Now I am writing here in short summary -
so whats the difference between Destination host Unreachable and Request timed Out . When you ping a particular IP an ICMP payload is generated , a packet is generated which is sent through the network to the destination . There are many steps involved in this which I wont explain now .
When the packet does not reach the destination IP due to the unavailability of the IP in the routers routing table or the IP is down on the network or the server is down or other reasons you will get a ” Destination host Unreachable” message
In the other case the packet reaches the destination IP or Server and while on the return trip to the source it gets dropped due to some reasons you will get a “Request Timed Out” message
Now in the end I am tell you that We are found that ISP Backbone is faulty.
