[vpn-help] Debian 8 Jessie broke ShrewSoft Client

[Aaron Ciarlotta]

https://serverfault.com/questions/848574/cant-connect-to-vpn-with-shrewsoft-from-debian-8-7

It was working fine in 7.7. The connection still works in Debian 8, but 
does not route any packets through the tunnel. We've exhausted all 
settings. Identical iked.conf and sysctl.conf settings works perfectly 
in CentOS 6.8 with the same StrongSwan server, and a Windows client on 
the same network works fine with the same server.

What did they break in Debian 8?