A past MSP configured our Windows servers (2012 R2) like so:
- SERVER01 (10.0.0.1): DC + DHCP + DNS
- SERVER02 (10.0.0.2): RRAS
DHCP is handing out IP addresses in the 10.0.0.50-240 range.
DNS is configured for secure dynamic updates, and DHCP uses a credential to register updates in DNS.
RRAS is providing an SSTP VPN, using a single NIC, and is configured to assign IP addresses using DHCP (rather than a static address pool). It has a DHCP Relay Agent set up on the "Internal" interface with 10.0.0.1 in the server list.
All of that is fine when domain-joined laptops are in the office connected directly to the network, because DHCP updates the DNS whenever they renew their leases.
However, when those same laptops are taken out of the office and connect to the VPN, the DNS does not get updated with their new IP addresses, so I can't perform any kind of remote management or deployment using their hostnames until they're brought back to the office.
How do I get the DNS to correctly update with the VPN clients' IP addresses?
Enabling the "Register this connection's addresses in DNS" option on the VPN clients doesn't work because the existing DNS records are owned by the DHCP credential, so the VPN clients do not have permission to directly update the records. (I've verified this by manually giving one of the laptops permission to write to their own DNS record, at which point it was suddenly able to register in DNS via the VPN).
Also, running "ipconfig /all" on the VPN clients shows "DHCP Enabled: No" for the PPP adapter. Is that the expected behaviour? Shouldn't it say "DHCP Enabled: Yes" if the DHCP Relay Agent is actually working?