I am using strongswan 5.1.2 on Ubuntu and have installed it using apt-get. I am trying to upgrade to strongswan 5.7.1. I first removed the current installation using the following commands:

sudo apt-get --purge remove strongswan
sudo apt-get --purge remove strongswan-plugin-xauth-generic
sudo apt-get autoremove

I'm building strongswan from source using ./configure --prefix=/usr --sysconfdir=/etc --enable-monolithic. When I run sudo ipsec start --nofork I get the following error message:

charon refused to be started /usr/libexec/ipsec/charon: error while 
loading shared libraries: libhydra.so.0: cannot open shared object 
file: No such file or directory

From my understanding libhydra has been removed and does not exist in 5.7.1 so this is probably something left over from the previous version which hasn't been removed properly

Can anyone help me with this?

1 Answer 1


Yes, you probably didn't remove all packages.

In Ubuntu 14.04 (which shipped 5.1.2) strongSwan was split into lots of packages, in particular, because most plugins had their own package, see Ubuntu's source package page. The charon daemon is part of strongswan-ike, the ipsec script is in strongswan-starter, the libhydra library in the libstrongswan package.

So make sure you have all of them removed before installing the self-compiled version. Check which strongSwan-related packages are still installed with e.g.:

dpkg-query -l '*strongswan*'

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