Sorry for the late reply. It's been a busy summer :-/
I needed the vpn today and suddenly it wasn't working. This is most likely because of a recent update. I had 1330 package updates waiting
I noticed that the "IPsec Settings" button had disappeared from "Point-to-Point Tunneling Protocol (PPTP)". Instead I am using "Layer 2 Tunneling Protocol (L2TP)".
But still it wasn't working, so I've been Googling and experimenting for a few hours. For me, the answer was here: https://askubuntu.com/questions/9042...u-16-04/909380
Apparently the VPN server is using a legacy cipher that resent strongSwan versions consider to be broken.
So now I set it up like this:
- Open “Settings” via “Activities” or the menu next to your battery indicator.
- Go to "Network" and press the [+] button in the bottom left corner of the dialog.
- Choose "Layer 2 Tunneling Protocol (L2TP)"
- Fill in "Name", "Gateway" and "User name"
- Press the "IPsec Settings" button
- Select "Enable IPsec tunnel to L2TP host"
- Fill in "Pre-shared key" (I leave the "Gateway ID" field empty)
- Set "Phase1 Algorithms" to 3des-sha1-modp1024
- Set "Phase2 Algorithms" to 3des-sha1
- Press "OK", then "Apply"
Hope this helps