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DHCP not working on T26P when OpenVPN is enabled. - Printable Version

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+--- Thread: DHCP not working on T26P when OpenVPN is enabled. (/showthread.php?tid=11399)

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RE: DHCP not working on T26P when OpenVPN is enabled. - mfvianna - 07-03-2016 04:42 AM

(02-24-2016 09:59 PM)pdugas Wrote:  I'm getting bit by this little nasty as well. Can't reliably switch from using a FQDN to an IP because our VPN server is on a dynamic circuit. Need a fix for this ASAP please.

Oh, I'm using a T22P running the current 7.73.0.50 firmware. Pls fix.

I had to fight with this bug for a few hours before getting into an acceptable workaround.

The bug seems to happen because OpenVPN tries to resolve the FQDN before the phone gets its IP and for some reason it then avoids the phone to get the IP, even if we tell OpenVPN to not attepmt indefinitely (i.e., resolv-retry infinite).

The workaround that worked for me is to fool OpenVPN in the first attempt so that the next time, when it retries 5 seconds later, the network is already available:

Here is the trick:

Where you define your remote in the vpn.cnf like this:
remote whatever-fqdn.you.use port-number

You add a line before it containing a loopback interface reference:
remote 127.0.0.1 any-port-number
remote whatever-fqdn.you.use port-number

For obvious reasons the first server will fail and after 5 secs, OpenVPN will try the second. At this point, the network will already be functional and the FQDN resolution will work.

Hope it works for you too.


RE: DHCP not working on T26P when OpenVPN is enabled. - 1sae - 05-12-2021 10:46 AM

I hate to revive an old thread, but I'm finally getting around to use VPN for the first time on my old t28p for some users that are now working remotely. After a lot of work trying to figure out all the settings on these phones I finally got it working only to find there's this issue. Was this ever fixed?