07-15-2008 11:12 PM - edited 03-06-2019 12:13 AM
I have a DHCP server in my first VLAN (101) and it hands out addresses without problem. When I attache a client to another VLAN, no DHCP address. I have an IP helper address in each VLAN as well as the VLAN IP as the gateway on the scope (Windows Server 2008) but nothing.
IOS Native 12.2
Thanks!
07-15-2008 11:15 PM
and I can ping across the VLANS, ping the DHCP server as well. Thanks for any help.
07-15-2008 11:48 PM
Hi
Under u r vlan SVI's issue the command
ip helper-address (address of the dhcp server)
Thanks
Mahmood
07-16-2008 07:02 AM
Yes, I did enter the IP helper-address of the DHCP server under each VLAN interface.
07-16-2008 09:45 AM
Does the scopes subnet match up with the VLAN interface's subnet?
Also just a quick check that the pc is not set up for static addressing. Don't want to be burned by that one.
Also verify that the port you are plugging into has been assigned to the proper vlan and the command is "switchport access vlan xx"
Other than that, the config is basic. Just use the ip helper to direct the DHCP requests to the server.
07-16-2008 01:14 PM
Does the scopes subnet match up with the VLAN interface's subnet?
Check.
Also just a quick check that the pc is not set up for static addressing. Don't want to be burned by that one.
lol, check
Also verify that the port you are plugging into has been assigned to the proper vlan and the command is "switchport access vlan xx"
check.
Other than that, the config is basic. Just use the ip helper to direct the DHCP requests to the server.
Any other ideas, I've performed all the above commands as well as the helper address.
07-17-2008 10:21 AM
Have you looked at your server and see if the DHCP requests are reaching it? If you don't see it, we can at least verify that the traffic is actually not getting there. If you see it, then the problem could be something local to the VLAN.
Have you tried sniffing the traffic on the clients as well? Hopefully you'll see the DHCP traffic on the VLAN. Just want to eliminate the possibility that a rogue DHCP server is not sending NAKs to your machine causing the machine discard the DHCP offers.
07-19-2008 11:46 AM
It turns out the DHCP was never authorized, but it would still hand out addresses in the first scope. Authorized the DHCP server with AD on server old network, and it's now handing out ip's across the vlans. Thanks for all the great suggestions!
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