Packet INternet Gropher (mostly known as ping) uses the ICMP protocol’s mandatory ECHO_REQUEST datagram to elicit an ICMP ECHO_RESPONSE from a host or gateway. ECHO_REQUEST datagrams (‘pings’) have an IP and ICMP header, followed by a struct timeval and then an arbitrary number of “pad” bytes used to fill out the packet.
We use ping mostly to check the connectivity between servers/client machines, network devices (routers & switches). When performing a ping to any device, different responses are received. Let’s understand them in detail.
Destination host unreachable.
The above response means the issue is with your machine’s network. Either a network card is not attached/installed OR network cable is not connected properly. Start to check from your network adapter.
Reply from 192.168.1.1: Destination net unreachable.
If you are connected to a modem OR in a network, the above response means the network device is unreachable. The network device can either be a modem, switch OR your router.
Request timed out.
The above message states that the remote machine/server is not responding. It can be down, not in the network, etc. It can also be due to ICMP requests disabled OR your IP blocked/blacklisted in the server firewall. Contact your system administrator OR web hosting provider to delist/unblock it.
Reply from xx.xx.xx.xx: bytes=32 time=574ms TTL=50
The above response means that the remote machine/server is accessible over the network. The time you receive this response, machine/server & services can be accessible.
Understanding the ping response will help you to troubleshoot the issues in a better way & in right direction.