[SOLVED] How To Control DHCP Lease In OpenVPN

[blueaquan]

Hello Everybody
My OpenVPN configuration is working perfectly alright with Active Directory authentication. However, I noticed that the IP address that's assigned to the Client Machines from the Server is for a period of one Year.
Is there a way to control this Parameter? If yes, I would like to bring this down to one day. Could you kindly help?


Thanks

Blue

[Mimiko]

who is serving DHCP requests: OpenVPN or some other DHCP server? If OpenVPN - its not a problem. If some DHCP server on LAN - you have to configure it. It's out of scope of OpenVPN.

[janjust]

the 1 year DHCP lease is assigned by OpenVPN itself; it can be controled (on the CLIENT side for Windows clients using

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ip-win32 dynamic [offset] [lease-time] 

e.g.

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ip-win32 dynamic 0 3600

[blueaquan]

Hi Mimiko and Janjust
The Lease is served by OpenVPN, however it would be great if there was a simpler way to do it on the OpenVPN Server rather than on individual client machines...


Thanks
Blue

[janjust]

In a 'tun' style network the DHCP lease is done by the OpenVPN *client*, not the server. The OpenVPN client program acts as a mini DHP client to the local tap-win32 adapter.
If you want to have a server side DHCP server then you need a 'tap' style network, possibly using bridging (which I would NOT recommend)

On the server side you might be able to get away with

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push "ip-win32 dynamic [offset] [lease-time] "

[blueaquan]

Hi Janjust
I have a bridge mode setup on my Network with OpenVPN running on FreeBSD 8.0 serving Win XP clients. Therefore I should be able to use the option you mentioned in my "server.conf" file...?
Also what's the Offset parameter? Could you kindly give me an example please...?


Thanks
Blue

[janjust]

I've never tested if this works, but it just might: add

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push "ip-win32 dynamic 0 3600"

to the server.conf file, restart the openvpn server and reconnect the clients.

[blueaquan]

Hi Janjust
Congratulations! it worked! I added the push ip-win32 directive to my server.conf file and the lease now shows one day.

Thanks to you and everybody in this thread.

Blue

[janjust]

great to hear that - this is one for the FAQs

closing topic.