General discussion


DHCP can't Connect

By mingteikg ·

Trying to connect to my ISP using DSL with WANPPPoE. However, I need to have
the IP assigned by DHCP and not through Automatic Private Server. However, I
did some test using "netsh" and found out that it can't connect to the DHCP

I did the "netsh int ip reset reset.txt" and this only gave me the Assigned
by DHCP temporary in the status of my LAN (NIC card). When I off the Aztech
305E switch and on it back again, it still didn't work.


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by compgirlfhredi In reply to DHCP can't Connect

When Windows starts, TCP/IP attempts to find a DHCP server on attached network to obtain dynamically assigned IP addresses.An absence of a DHCP server, the client can't obtain an IP address. Auto Private IP Addressing (A P I A )generates IP address in network that client generates and subnet mask of
Microsoft has reserved through and uses this range of addresses to support Automatic Private IP Addressing.
After generating address, client computer broadcasts,then, if no other computer responds, assigns address to itself.
The computer continues using this address til a DHCP server is installed on the network. The computer detects and receives configuration information from the DHCP server,allowing computer to be connected to a LAN hub, to restart without any IP address configuration information, and to be able to use TCP/IP for local network access.Although A P I A can assign IP address to DHCP clients automatically, it doesn't generate all the info that DHCP typically provides, ie: address of a default gateway. Consequently, computers that are enabled with A P I A can communicate only with computers on the same subnet that have been assigned addresses through A P I A.Therefore I disabled my A P I A.
You can disable Automatic Private IP Addressing to prevent computers from automatically being assigned IP addresses. This ensures invalid IP addresses are not assigned to computers if a DHCP server fails.By default, the A P I A feature is enabled. You can disable this by adding the IPAutoconfigurationEnabled entry to the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services \Tcpip\Parameters\Interfaces\GUID_of_the_adapter subkey in the registry.
The IPAutoconfigurationEnabled entry takes a REG_DWORD data type. To disable Automatic Private IP Addressing, specify a value of 0 for the entry.
Keep in mind that ALL SITUATIONS are NOT created equal! (my setup and situation differ from yours)Implement this at your own risk.

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by mingteikg In reply to

Thanks for your reply.

Since this is a stand alone PC, where will it connect to the DHCP Server to get the IP??

Thanks again!! :-D

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by gdh19701 In reply to DHCP can't Connect

Are you able to ping any network from your command window?

In your Network Adapter, select TCP/IP properties and make sure "Obtain IP Address Automatically" is NOT selected, and instead have the assigned IP address from your ISP. Also make sure your DNS Server IP address is configured for the server your ISP provides.

You might want to check on your ISP's website to see if there are any network settings that need to be configured. There should be some information there to guide you to correctly configure your settings. If you cannot easily locate it, contact your ISP's support desk for assistance.

Also, make sure your Aztech switch has the correct RJ-45 cable, as not all serve the same purpose. Some work from computer-hub, computer-switch, switch-switch, etc... You want a straight-through or standard ethernet cable. If you have a cross-over cable, you will encounter data collissions or no data at all.

If you cannot ping any other computer on your network, assuming you have more than one computer connecting to your ISP, you might have the wrong cable.

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by mingteikg In reply to

Sorry but this is a stand alone PC, with an ADSL modem (not a router/hub/switch).

The problem is, when I remove the RJ45 cable from this computer, and connect to the laptop, the laptop works. On the other end of the RJ45 is the modem.

Could it be a problem wtih my NIC? I changed the NIC and it still isn't working. What about my motherboard?

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by jose_12650 In reply to DHCP can't Connect

The IP address leased by the DHCP (Service Provider's DHCP) was specific to your laptop. It will not work with your other system unless you powered down your ADSL modem, or in the alternative, release the IP address from your laptop before connecting the RJ45 Cable to your other machine. The problem with your query is that you have not spelled out your scenario very well, thus generating some responses from the members based on a poorly laid out scenario.

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by mingteikg In reply to

No, I think you are the one who is misunderstanding...

It seems that my desktop can't connect out to the DHCP Server (ISP) to get an IP, so it's assigning it through Automatic Private Address.

Any ideas why it can't connect out (clean reinstall Windows isn't working either).

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by jose_12650 In reply to DHCP can't Connect

If you read your first query and your comment on the second answer, you will see that you have missed some important facts/details of your problem when your first posted the query. If I get lost in your query, it was chiefly because of the way you laid out your problem. I know that you are only a novice because you can't even decide if you have to change your NIC or not when all you have to do is to go to your device manager and find out if there is something wrong with your NIC.

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