Hi Techie,
You don't have a task bar at the bottom of your Win 95 screen? The thing with the Start button in the lower left corner? It is possible you are set for autohide mode such that you don't see it unless your mouse is down at the bottom edge of the screen. You get to properties of the TaskBar via Start->Settings->Taskbar. If you click the right mouse button on an icon for a task on the Taskbar, you get a menu that includes the Close command. This will either close the given application or put up a dialog for confirmation to close it. Also, if you right click the Taskbar itself (rather than an icon on it), you get a menu that includes a Task Manager command which opens up a Task Manager Application that gives you more info about things.
Screen space is like memory; there is never enough.
Re: "ping" means to send a number of information packets out to a server to see how fast the return time is... when the designated name server (DNS) is not functioning - i.e. the server is off-line, you get a dead message back. This could be the SI server, a power failure, a loacal area failure - hard to tell. You can do a traceroute ng.
This is sort of right. Ping relies on the ECHO service. If you ping a host and it is running the ECHO service and the network path to that host is healthy, then you will receive a response indicating roundtrip time. If the network is screwed up between you and the desired host then you won't get a response back and ping will report a timeout. Most pings send several messages. An infrequent timeout doesn't mean much but lots of timeouts or all timeouts is bad.
Some hosts do not run the ECHO service and you can get back misleading messages such as host unreachable even though it is reachable for the services it provides. A lot of mail servers do not run ECHO. For example, try ping mail99.internetmci.com. It reports "Destination net unreachable" yet I get my email from there just fine. You can telnet to its POP3 server.
DNS (Domain Name Server) is a separate issue. These are servers that translate domain names like talk.techstocks.com into IP addresses like 205.185.197.20. This is independent of being able to get to the host you want once you have the IP address. Of course, if your DNS is down or you can't get to it, then you can't resolve the domain name to get that address. If you know the IP address for a given host, you can substitute that for the domain name whenever your DNS is inaccessible and thus still get where you want to go.
Generally, you are set up for more than one DNS. ISP's give you the IP address for their DNS's, but you can actually use any DNS for which you know the IP address. This is part of your TCP/IP setup or your Dial-up set up. I suppose any DNS could deny service based on the requesting IP address (and thus support a limited set of users) but I haven't experienced this.
TRACERT is also pretty cool but it too can be misleading. It tries to show you all the hops on the path between you and a desired host. It is based on a bit of a hack using the Time-to-live (TTL) field which is the maximum number of hops a message should travel before giving up. It sends a message to the desired host with a bogus port and a TTL of 1, and more with TTL's of 2, 3, 4, etc. The first message "times out" ie hits the max hops at the first node so the first node reports this back to the origin host. This error message tells you who the first hop is. The second message with a TTL of 2 makes it to the second hop before its TTL expires and so the second hop replies with an error and you know who that is. When a message finally makes it to the desired host, it reports a different error because of the bogus port and TRACERT knows it is done.
The problem is that not all hosts report these errors correctly or report them at all. So you can get a "* * * timeout" simply because the given node did not respond correctly to the TTL timeout even though it transports and routes packets as it should. The number of such misbehaving hosts is small but they exist.
Suffice it to say that when TRACERT gives you a nice clean path, things are fine. When it doesn't, things may be ok or may not but are in any case suspect. And you have some idea where a problem might be but there are no guarantees here.
Wow, that got long. Hope it's helpful. |
