Stuck at Requesting an IP address to the DHCP server in VPN

Post your questions about SoftEther VPN software here. Please answer questions if you can afford.
Post Reply
Dario0806
Posts: 1
Joined: Sun Jan 17, 2021 6:32 pm

Stuck at Requesting an IP address to the DHCP server in VPN

Post by Dario0806 » Fri Jan 22, 2021 8:38 pm

Hi, I have a big problem that I already spent hours on trying to fix it.

So this is not my first time using SoftEther, I already installed it successfully in few companies, but this week I have big problems.
When I try to connect to any other SoftEther Server that I already installed, from my PC SoftEther Client, I see the authentication screen for a split second and after that the screen that shows me my IP in the VPN, and that is it, VPN works like a charm.

But in this installation, I do not know what I did wrong. When I try to connect to the server authentication passes, "connection successfully" or something like that, and then "Requesting an IP address to the DHCP server in the VPN..." and it is there for like 10 seconds, and then it despairs, like it was canceled or something, but there is no message about what IP I got. When I looked in cmd "ipconfig", my IP was 169.254.232.30, which is not even close to 192.168.1.x that it should have been. And it basically does not let me ping anything in the network of course.

So few things that you might find useful if you try to help me:
1. Local bridge is configured to the right adapted
2. The SoftEther server is installed on Windows Server 2016 Essentials, and in network adapters there are two NIC adapters and one Microsoft Network
Adapter Multiplexer(if I understood correctly that uses both NIC adapters? First time seeing this to be honest). Does this adapter have anything to
do with my problem since all the servers where I installed SoftEther Server before were using only one NIC?
3. I'm listening to port 5555, and it is also forwarded on the router. Am I missing any ports?
4. Tried turning off the firewall if it would help in any way, but it did not.
5. I checked both SoftEther Server logs and SoftEther Client logs, and it was clean of any errors.

Can anybody help me with this please? I don't have any ideas what else to do.

ethanolson
Posts: 50
Joined: Mon Dec 02, 2019 6:29 am

Re: Stuck at Requesting an IP address to the DHCP server in VPN

Post by ethanolson » Wed Jan 27, 2021 11:50 pm

I think I ran into this issue with a virtual machine and the virtual switch wasn't set to promiscuous mode. Also, Meraki gear and other security-conscious gear can block this stuff.

johncarl.santos
Posts: 8
Joined: Sun Oct 25, 2020 3:51 pm

Re: Stuck at Requesting an IP address to the DHCP server in VPN

Post by johncarl.santos » Sat Mar 06, 2021 7:27 pm

any solutions for this?

I have set nopromiscuous mode on VPN Server to true already but still. my VPN clients does not get IP Address from my virtual machine VPN Server

nobody12
Posts: 139
Joined: Sat Feb 13, 2021 10:22 pm

Re: Stuck at Requesting an IP address to the DHCP server in VPN

Post by nobody12 » Sun Mar 07, 2021 8:18 pm

Please give more details.
On what platform did you install the Server?
Win/Linux/mac?
What OS is used?
Vitrual Machine or not?

rox
Posts: 2
Joined: Wed Feb 23, 2022 8:53 am

Re: Stuck at Requesting an IP address to the DHCP server in VPN

Post by rox » Wed Feb 23, 2022 10:00 am


I had something very similar.

Client-1 can connect reliably. Client-2 gets an IP address only the first time it connects. After that it sits at the 'Requesting address' dialog for about 10 secs but no address is assigned (it gets an APIPA 169.254 address, so the VPN connection doesn't pass IP traffic). If I delete the virtual network adapter from client-2 then create a new one it usually works for one connection, then the problem returns.

The problem was that Client-2 had the DisableDHCPMediaSense flag set, as follows:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters
Name: DisableDHCPMediaSense
Data type: REG_DWORD
Value: 1

I renamed the key to disable it (reverting to the default behaviour). A reboot was required to take effect. Some TCPIP properties can also be set at the interface level - I don't know if that is possible in this case, but it may be worth checking in each node under 'interfaces'.

VPN Server: Windows 10 VM on some Windows Server host.
Client-1: Windows 10 VM on some Windows Server host.
Client-2: Windows 10 on bare-metal.

solo
Posts: 1215
Joined: Sun Feb 14, 2021 10:31 am

Re: Stuck at Requesting an IP address to the DHCP server in VPN

Post by solo » Thu Feb 24, 2022 1:46 am

Interesting case @rox. Why did Client-2 set the DisableDHCPMediaSense flag before? By default it is not set. It may be useful for multicast issues. What else?

rox
Posts: 2
Joined: Wed Feb 23, 2022 8:53 am

Re: Stuck at Requesting an IP address to the DHCP server in VPN

Post by rox » Fri Feb 25, 2022 6:55 am

solo wrote:
Thu Feb 24, 2022 1:46 am
Why did Client-2 set the DisableDHCPMediaSense flag before? By default it is not set.
Seems it was set by the installer of some software with multicast functionality. I hope this helps others who may encounter the problem of getting stuck at "Requesting an IP address to the DHCP server in the VPN" - it wasn't easy to track down!

Post Reply