Model :

Hardware Version :

Firmware Version :

ISP :

Hi TP-LINK,
I have a C9 (hardware revision 3). I have been experiencing L2TP/IPSE passthrough issue. The L2TP server is behind the router. I have to put the L2TP's host in DMZ, OR disable SPI firewall, otherwise I CAN NOT Connect to the L2TP VPN server. I also have these 3 UDP ports defined in NAT / Virtual Server table: 1701, 500, 4500.

Is it an expected behavior or it's a bug in the firmware? My friend has a C7, his L2TP VPN server is working while C7 has SPI firewall ON.

Thanks!

Best regards

Kelvin