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Re: [Openvpn-users] 1.6 beta DHCP expires

  • Subject: Re: [Openvpn-users] 1.6 beta DHCP expires
  • From: "James Yonan" <jim@xxxxxxxxx>
  • Date: Tue, 20 Jan 2004 02:12:54 -0000

Doug Lytle <support@xxxxxxxxxxxxxxx> said:

> James,
> Did you take into account that DHCP addresses have an expiry time.  1.6 
> has a 5 minute expire time frame.   I went to check my system at home 
> and found that the tunnel was down and it had lost it's IP address.

Right, the leases are given out for 5 minutes, but Windows should try to renew
the lease indefinitely and 1.6 will respond positively to renewal requests.

The lease is given for a short period of time so that the IP/netmask
association with the adapter will go away quickly if/when OpenVPN shuts down.

In my testing on XP, the DHCP client on Windows tries to renew usually about
50% of the way through the lease.  Which Windows OS are you using?

Are you saying that the renewal is not occuring, so that the address is lost
after 5 minutes?

Right now I am passing the DHCP option DHCP_LEASE_TIME (code 51) by default
(with a value of 5 minutes).  It's possible that I also need to pass
DHCP_RENEW_TIME (code 58) and/or DHCP_REBIND_TIME (code 59) to be more
compatible with all DHCP clients.  I didn't add these because the XP DHCP
client didn't seem to need them.

Any DHCP experts out there who care to comment?


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