"In Win2K the TCP/IP is set to 192.168.0.1 but it failed to response to Dos Prompt Ping. When pinging the host name, 127.0.0.1 appeared. Why?"
127.0.0.1 is ALLWAYS the local (host)address for TCP/IP. It is supposed to be the IP of your local machine's TCP/IP stack including the physical layer (ethernet card) per Microsoft.
Normally if you suspect that TCP/IP may be corrupted, you can ping 127.0.0.1, and if you get good responses, then your TCP/IP, your bindings, and your ethernet card should be functional. This is all founded on the OSI model (7 layer burrito):
Application (top)
Presentation
Session
Transport
Network
Data
Physical (bottom)
When you "ping", you are originating a request at the Application level which "suppposedly" has to travel all the way down to the Physical layer and back up to Application to return a response (ping statistics).
What a co-worker discovered thou was that it will return good responses even with the ethernet card removed. We contacted Microsoft's engineering division, and relayed this finding to them, and they said "Hm.... We'll get back to you". We have not heard back from them yet.
I suspect that TCP/IP uses a "Virtual" socket for 127.0.0.1, and only simulates a hardware response. The real activity is all in software. Your ethernet card also has a MAC address. This address "should" be hard wired individually for every network card made, and should be unique. It is usually expressed in Hexidecimal like this:
01 10 5e 1f c3 6a
At a DOS prompt, type in {netstat ?} and you will get a list of command modifiers for the netstat command. These will give you more detailed information about your network addressing. For instance if you enter {netstat /r} you will see your current Routing table and statistics.
Or in W95/98 go to the RUN line and enter {winipcfg} and hit enter. A new window will open, and you can select either PPP (dialup connection) or your Ethernet card. This will show all settings including TCP/IP address, MAC address, Default Gateway, Sub-Net Mask, etc..
Any time you change your settings in your network, you should either Release ALL and Renew ALL in this window, or within a DOS window use {ipconfig /release all} and then {ipconfig /renew all}. This tells your computer to relook at your configuration, and change any settings currently in use by your network. If you make changes to TCP/IP, DHCP, etc... you MUST either shut down and restart, or use those previous commands to enable your settings changes to be modified in the network tables.
When you configure your TCP/IP properties, you can choose to either use DHCP from a remote host for TCP/IP addressing (your ISP usually provides this service) or you can purchase a static IP and "hard code" the IP, Sub-Net Mask, and the Default Gateway. You could get fancier in several ways, like configuring your server as global DHCP client, local DHCP server, letting it pass out local IP addresses, and function as a Gateway for the rest of your local network, or using a static IP on the server, and DHCP internally, or ......
All different configurations have their advantages and disadvantages depending on your situation.
Hope this helps.....
HelpDeskAnalyst
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