Technical Tip: Custom DNS servers are not supported with L2TP tunnels

[nverma]

Description	This article describes how custom DNS servers are not supported with L2TP tunnels.
Scope	FortiGate.
Solution	Custom DNS servers are not supported with L2TP tunnels. Users connected via L2TP will always retrieve FortiGate system DNS servers. To change the configured DNS servers in GUI, Network -> DNS, then set the primary and secondary DNS servers. With the CLI: config system dns     set primary x.x.x.x     set secondary y.y.y.y end Changing the system DNS is a global change and does not affect only L2TP. The FortiGate will now use the configured DNS servers for DNS queries. It is possible to configure custom DNS servers on the L2TP adapter in Windows by editing the Internet Protocol Version 4 (TCP/IPv4) settings. Example: When the L2TP VPN is connected, use ipconfig /all in Command Prompt or PowerShell to verify the custom DNS servers are configured. Related articles: Technical Tip: How to configure L2TP using interface/route based IPsec VPN Technical Tip: Resolving Internet Connectivity Issues with L2TP IPsec VPN Using Windows Native Clien... Troubleshooting Tip: L2TP in IPsec connectivity issues