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Question
Friday, June 12, 2015 9:20 PM
This one is driving me crazy, I know short short drive.
Set up a new dhcp server, windows 2012 r2 with latest patches. Windows firewall disabled on server. I have the scope properly configured on server because when i move the dhcp server to the same subnet that has a dhcp client the client receives an ip address. When i move the dhcp server to another subnet and the change is made in the router that the client is in to point to the new dhcp server it no longer receives an ip address
Changing the ip helper statement in the router for a vlan always worked with our windows 2003 dhcp servers but i'm missing something in 2012 r2
lars
All replies (7)
Thursday, June 18, 2015 5:40 AM ✅Answered
Btw, to use VLAN tagging you need a trunk port. But asuming your DHCP Server can communicate through its default gateway it is probably configured correctly.
Boudewijn Plomp | ITON Consultancy
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Thursday, June 18, 2015 8:13 AM ✅Answered
If that switchport is an access port rather than a trunk it isn't going to work correctly with VLAN tagged VMs. Period. Get your networks team to reconfig the switch port/s first then try again.
Sunday, June 14, 2015 9:46 PM
Windows Server 2012 R2 works exactly the same, nothing has changed. Make sure you auhtorized your DHCP Server with the correct IP Address. I just mention to be sure since you moved the DHCP Server between VLANs. And of course make sure you configuered a default gateway.
Boudewijn Plomp | ITON Consultancy
Please remember, if you see a post that helped you please click "Vote as Helpful", and if it answered your question, please click "Mark as Answer". This posting is provided "AS IS" with no warranties, and confers no rights.
Tuesday, June 16, 2015 9:51 AM
Hi,
If the problem still exits, you may considering of using Network Monitor to capture ICMP packets(ipconfig /renew/release), compared with normal packet, it might be helpful to find out the problem.
Best Regards,
Eve Wang
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Wednesday, June 17, 2015 4:12 PM
sounds to me like you are missing DHCP relay or "DHCP Helper Addresses" for your different VLANs. you will need this on the router responsible for your VLANs and/or potentially on you L3 switches.
the Cisco command is:
interface Vlan5
description *** Server VLAN ***
ip address 172.x.x.x 255.255.255.0
** ip helper-address 10.x.x.x**
10.x.x.x is your DHCP server
EDIT...
Have you virtualised your DHCP server?
If so are your uplinks on the host trunk ports and is the VM VLAN tagged?
Wednesday, June 17, 2015 8:29 PM
dhcp helper statements are done by our network team. I can't do that. I saw them configure the ip helper statement on the l3 switch and it does point to the new dhcp server.
it is a virtual server. My uplink is a access port and the vm is vlan tagged.Think i'll run some wireshark traces
lars
Thursday, June 18, 2015 5:43 AM
A question. Is your old IP-Helper to the old DHCP Server still configured as wel?
Boudewijn Plomp | ITON Consultancy
Please remember, if you see a post that helped you please click "Vote as Helpful", and if it answered your question, please click "Mark as Answer". This posting is provided "AS IS" with no warranties, and confers no rights.