August 10th, 2003, 02:10 AM
Something i dont understand. I ping this web site www.di.fm and it doesnt lose any packets no timeouts or anything and i go to visit the page i get the 404Not found. Anyone get it?
August 10th, 2003, 02:49 AM
works fine for me ... wish they had radio station on a car like that lol i wouldnt leave the car )
Un Seen But Well Heard Of
August 10th, 2003, 03:18 AM
it worked for me too but for future reference pinging a computer and getting a reply does not mean that it is running a webserver, it just means that it is online and responding to pings. to ensure it has a webserver running you would want to scan port 80.
August 10th, 2003, 04:01 AM
Hey thx guys, i guess their software was temporarily down.
August 10th, 2003, 05:11 AM
cire has a pretty good response, here's a bit more info. Since this is noob stuff, I'll use an analogy to the postal mail system.
In this analogy, a service on a machine is like a person (Alice) reading and answering their mail. A machine is composed of a bunch of clustered services, so let's say it's a town.
Pinging a server sends a special type of packet (ICMP) to the server. This kind of packet is handled at a very low level, a machine can be barely functioning and still reply to pings. In our analogy, pinging a server is like asking the postal service if they deliver mail to a certain town. It doesn't mean that Alice here even has a mailbox in that town, just that the town can receive mail.
cire mentioned portscanning. Most port scans do not tell you if a service on the machine is running properly, merely if the operating system is prepared to accept connections on a given port. In our analogy, having an open port is like having a mailbox. Just because Alice has a mailbox doesn't mean she's actually reading her mail. Perhaps she's on vacation, and the letters are just queuing up.
Another test is actually connecting to the machine with a web browser. This is like sending a letter with signature confirmation. You connect and send your request, and either it times out (Alice never picks up her letter), or you get something back (Alice picks up the letter and you get a message back saying so). Note that this does not mean that Alice actually did anything useful with your letter, she could have dumped it in the trash outside the post office. This, incidentally, was your situation. The server was up and running, but the files in the site were missing, so it wasn't doing anything useful.
The final test is actually looking at what you get back. Does the site work properly? This is like Alice reading your letter and doing something useful with it, like writing you back or filling out a Form 1500 or whatever.