CentOS8 and vpnc

VPNC packages are missing from CentOS8 and EPEL 8. Furthermore, recent RPMs from Fedora will not install on CentOS8 because rpm is apparently missing zlib compression support. For this reason, if you want to connect to vpnc I suggest you rebuild the SRPMs. I used:

  NetworkManager-vpnc-1.2.6-4.fc32.src.rpm
and
  vpnc-0.5.3-37.svn550.fc32.src.rpm

And those packages got everything working for me from the command line on CentOS8.