l2tp over ipsec on mac osx 10.13.4 I want to find l2tp over ipsec in macOS 10.13.4 but only get l2tp/ipsec. 
Is l2tp over ipsec canceled ?

I tried to select the option and connect VPN. But it is not working and I get the connection log:

Sat Sep 15 13:18:12 2018 : publish_entry SCDSet() failed: Success!
Sat Sep 15 13:18:12 2018 : publish_entry SCDSet() failed: Success!
Sat Sep 15 13:18:12 2018 : l2tp_get_router_address
Sat Sep 15 13:18:12 2018 : l2tp_get_router_address 192.168.12.1 from dict 1
Sat Sep 15 13:18:12 2018 : L2TP connecting to server 'xx.xx.xx.xx' (xx.xx.xx.xx)...
Sat Sep 15 13:18:12 2018 : IPSec connection started
Sat Sep 15 13:18:12 2018 : IPSec phase 1 client started
Sat Sep 15 13:18:12 2018 : IPSec phase 1 server replied
Sat Sep 15 13:18:13 2018 : IPSec phase 2 started
Sat Sep 15 13:18:13 2018 : IPSec phase 2 established
Sat Sep 15 13:18:13 2018 : IPSec connection established
Sat Sep 15 13:18:13 2018 : L2TP sent SCCRQ
Sat Sep 15 13:18:14 2018 : L2TP received Auth Challenge AVP - not supported
Sat Sep 15 13:18:14 2018 : L2TP received SCCRP
Sat Sep 15 13:18:14 2018 : L2TP sent SCCCN
Sat Sep 15 13:18:14 2018 : L2TP sent ICRQ`
l2tp/ipsec is equivalent to l2tp over ipsec. The / in technical English is often spoken as the word over.

You can find L2TP over IPSec in the Network System Preference settings:


Launch System Preferences
Select Network
Select +
Select Interface VPN
Select VPN Type L2TP over IPSec