Can someone please explain what a ping and trace route are and how is it that something that shows as “down” is pingable?
Ping is great for checking if your internet is really down, or if it's a software issue that's preventing you from getting online.
ping in simple word it is just like a making any action on any remote application to insure the working or connectivity and trace route is nothing but the action of capturing the source system information........
You already have the fundamental explanations of ping and traceroute in the previous answers. As for addresses being "ping-able" but not online there are multiple reasons.
For example the server could be online but the service not. In that case pinging host X might work while the website on host X is not available (Port 80 not reachable, httpd not running, etc.).
Even hosts that are actually shutdown can be "ping-able". That is because most modern network cards power down into a standby state (unless you pull the power cord to the system). They are then running in a 10Mbit Half- or Full-duplex state and will continue to respond to ping requests. This state is used e.g. for Wake-on-Lan functionality.
Mostly ping is used to make sure DNS is working, the TTL (Time to Live) is not too short to time out requests and a host reachable in general e.g.
PING makeuseof.com (184.106.121.xxx): 56 data bytes
64 bytes from 184.106.121.xxx: icmp_seq=0 ttl=45 time=116.655 ms
64 bytes from 184.106.121.xxx: icmp_seq=1 ttl=45 time=115.730 ms
trace route is used to (a) see how many "hops" (stations, routers, gateways) are in between you and the traced host and/or (b) follow the geographical route from your system to the server.
traceroute to makeuseof.com (184.106.121.xxx), 64 hops max, 52 byte packets
1 10.3.0.254 (10.3.0.254) 2.784 ms 1.987 ms 0.500 ms
2 80.121.153.x (80.121.153.xxx) 2.238 ms 2.071 ms 0.736 ms
3 172.17.109.xxx (172.17.109.xxx) 1.734 ms 2.969 ms 2.235 ms
4 195.3.68.xxx (195.3.68.xxx) 2.496 ms 2.567 ms 2.190 ms
5 195.3.70.xxx (195.3.70.xxx) 2.696 ms
195.3.70.xxx (195.3.70.xxx) 2.782 ms 2.566 ms
6 ams-ix.ae1.cr1.ams2.nl.nlayer.net (195.69.145.xxx) 23.709 ms 24.199 ms 25.728 ms
This is only a portion of the trace route. It shows my local gateway (10.3.0.254), the internet gateway, our modem (80.121.153.xxx), hops 3 to 5 are servers at my providers end and hop 6 shows that my requests to MUO are routed through "ams2.nl.nlayer.net" which basically is a server in an Internet Exchange in Amsterdam, Netherlands.
ping is command that is used to check the connectivity between the systems and trace rt is used to know the networking devices the data will go through before reaching the destination
I assume the questioner already knows this but answers on MakeUseOf are read by others so...
Why not try using Ping/Traceroute, that gives some idea of what they do.
On a Windows PC get to the command line (Win 7 Start button>type cmd in the "Search programs and files" box, click on cmd.exe)
At the command prompt "...>" type ping makeuseof.com and see what happens.
Then try tracert makeuseof.com
One does not ping a site, but a machine. Traceroute also is only contacting the machine, not the server (software running a particular service). As long as a machine is powered up, connected to the network, and is configured to send ICMP replies (and any intervening routers and/or firewalls don't block the requests or replies), both traceroute and ping will work. As far as any server services such as a web server (HTTP/HTTPS), ftp server, telnet server, etc., they may not be running (the server service is down) even though the machine itself is alive and well on the network.
thanks Bruce, your explanation gave me a more complete picture to ha's helpful response i almost get it. as always i appreciate your time and patience, christine
Ping and Traceroute work by sending out ping packets and waiting for replies.
ping command is used to test whether there is a connection between the machine where you work and the specified machine. To do this, it sends every second control packets [Internet Control Message Protocol (ICMP) echo request packets] to the remote machine. Ping is used to count the time (in milliseconds, and records any packet loss) required for information to make the round trip between your computer and a server.
With Trace Route goes further than Ping. It allows you not only to know the time to go back and forth between a host and a second host, also to see the path between your computer and the other computer. Display the connection path to the chosen location since the internet path between two locations has several routers you can see how is structured hierarchy of servers on the Internet. Using this command, you can understand, if a website is slow, why it responds so long. More remote is the target computer more the road will be longer.
you can ping (Ping will use ICMP protocol) a site that is down as long as ICMP replies are enabled on the site provider. Ping only accepts hostnames (ping http://www.google.com
), not URLs
thank you ha your the best, i am definately printing this page so i can now figure out ICMP protocol. I almost get it, i'm just not seeing the whole picture in my head yet. i do understand what your saying which will make my studies easier. thanks ever so much for your time, christine