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NetworkingATE
1,545 pts.
 Why do some PCs on our network get an IP address automatically assigned and others don’t?
IP address, IP range, Network administration, Network management
When we connect a network cable to some PCs, it doesn't automatically assign an IP address and we need to manually assign an IP address. What is the benefit if the IP address takes automatically or not when we connect a network cable? Why do you think this is happening to only some of the PCs? Thanks.

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ASKED: December 10, 2008  7:42 PM
UPDATED: December 15, 2008  7:58 PM
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Answer Wiki:
Make sure that the PC’s NIC is set for DHCP in the network configuration. Also make sure that you have some free addresses available in your DHCP range. If you have 30 computers, and only 25 addresses then you would have problems. Also, most Routers will not try to assign an address via DHCP if there is already a matching static address, but best practice is to make sure your static addresses are outside of your DHCP Range. Good Luck! -Flame ============= Previous answer overwritten: Could be the switch ports are not negotiating link properly. Set the ports to full duplex, 100Mb/sec. Another possiblity is that the ports are members of a specific VLAN and not forwarding DHCP requests properly.
Last Wiki Answer Submitted:  December 10, 2008  9:03 pm  by  Flame   14,895 pts.
All Answer Wiki Contributors:  Flame   14,895 pts. , Labnuke99   32,645 pts.
To see all answers submitted to the Answer Wiki: View Answer History.


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Adding to the answer above:
______________________
Before going to great trouble checking your TCP/IP Scopes and such.
Here might be easier<
On the computers that do not lease an IP Address, do two things,
1. Right click on your LAN then click PropertiesHighlight on Internet Protocolclick Properties
From here simple make sure that the radio button is set to Obtain an IP Address Automatically and Obtain DNS server address automatically. Click Apply then OK.

2. From a command window type: ipconfig /flushdns {ENTER}
Then type ipconfig /release {ENTER}
Then type ipconfig /renew {ENTER}

If that does not clear up your issue, then use the answer from above.

This might save you some trouble

2kBoot
 105 pts.
 

Are the PC’s all on the same subnet? If not, you may have to enable DHCP forwarding on the interfaces away from the DHCP server itself. Plus, as mentionned above, check to see if there are still free addresses on the DHCP server.

Snapper70
 920 pts.