RRAS VPN clients do not receive IP from DHCP server

Question

_{Tuesday, July 14, 2015 6:42 AM}

I´ve setup RRAS with VPN, selected to use DHCP server and end result is:

RemoteAccess Event ID 20169: Unable to contact a DHCP server. The Automatic Private IP Address 169.254.90.105 will be assigned to dial-in clients. Clients may be unable to access resources on the network.

This RRAS acts as a gateway and NAT to all my interfaces, connecting every server and Client to each other via different NICs. These physical and virtual connections (NICs), works fine and IP adresses are received fine. Only the VPN interface doesn´t work. In RRAS IPv4 settings, I selected VPN nic to be the one to receive the adresses. DHCP server is able to ping that nic, and gateway is set correctly.

If I change the VPN DHCP settings to a static pool, it works, but I would like to use DHCP server

All replies (4)

_{Tuesday, September 15, 2015 6:44 AM ✅Answered}

VPN clients do not (and cannot) receive their config directly from DHCP. They must get it from the address pool in RRAS. You can set the pool to get its IP addresses from DHCP, or configure the static pool your self.

 There are a number of reasons for this, but the most obvious one is that the lease time of the config is for the duration of the connection, not the lease time of the DHCP server.

Bill

_{Wednesday, July 15, 2015 6:42 AM}

Hi Yannara,

Does the DHCP server is on the same subnet as the RRAS server? If not, you have to configure the DHCP relay agent, then you may check if the DHCP server address has configured correctly.

If the configuration is right, we can narrow down the scope of the problem by packet capture with network monitor.

On the DHCP server, we may check if the DHCP server has leased 10 IP addresses to the RRAS server. On the RRAS server, we may check if the RRAS server has received the response packet from the DHCP server.

Some references for installing RRAS as a VPN server:

https://technet.microsoft.com/en-us/library/dd458949.aspx

If you want to download the network monitor, you can click the link:

https://www.microsoft.com/en-us/download/details.aspx?id=4865

Best Regards，

Anne He 

Please remember to mark the replies as answers if they help and unmark them if they provide no help. If you have feedback for TechNet Support, contact [email protected].

_{Friday, July 17, 2015 7:07 AM}

Hello Anne,

- RRAS has many NICs, connecting Servers, Clients and VPN clients together. Every NIC = Different Subnet.

• One of RRAS´s NIC connects DHCP server directly. But VPN NIC is located in other subnet.
• DHCP replay are set to 2 different DHCP servers, I have 2 DCs working as DHCP clusters (sharing same scopes)
• I don´t see any VPN reservations on DHCP servers.
• There is no firewalls at all.

This is my Network/server infra, but I don´t have 10.0.6.0/24 VPN NIC+SCOPE discribed there yet:

_{Monday, September 14, 2015 5:57 AM}

Hi yannara,

As I have mentioned above, we could use network monitor to perform a network traffic capture on RRAS server, DHCP server and client to narrow down the problem.

We may find out where does the DHCP process block, then we may check the configurations on it. If the RRAS server send out request packets to DHCP server, but DHCP server can’t receive, we may check network connections between them, if DHCP server doesn’t send out request packets, we may check RRAS server's configurations or enable other irrelevant NICs and check if it will work.

Best regards,

Anne He

Please remember to mark the replies as answers if they help and unmark them if they provide no help. If you have feedback for TechNet Support, contact [email protected].