Destination is unreachable problem possibility under Linux using ping

Request time out and destination is unreachable when ping occurs

Request time out means that after the ICMP packet has been issued, there is a long absence of response, so the request is generated. Typically ping a host that does not exist in a network.

Destination is unreachable or destination port unreachable is typically a port or destination host unreachable ICMP packet that is received by the destination host or intermediate router response.

such as Ping a host with iptables sealed ICMP packet and use-j reject will appear destination port unreachable information, this is the response of the target host.

It is also possible that the forward chain has been dropped.

In general, the package has reached the target host, and then did not process to return information to you.

Reference:

http://blog.csdn.net/yzit0905/article/details/52748122 (The above sections are transferred from this article)

Destination is unreachable problem possibility under Linux using ping