title: how to solve the libgnutls.so.28 issue?
body: <pre><code>yum install autoconf automake gcc 
  libtasn1-devel zlib zlib-devel trousers 
  trousers-devel gmp-devel gmp xz texinfo 
  libnl-devel libnl tcp_wrappers-libs 
  tcp_wrappers-devel tcp_wrappers dbus 
  dbus-devel ncurses-devel pam-devel 
  readline-devel bison bison-devel flex 
  gcc automake autoconf wget
  </code></pre>
  
  <p>Install Nettle:</p>
  
  <pre><code>wget http://www.lysator.liu.se/~nisse/archive/nettle-2.7.tar.gz
  tar xvf nettle-2.7.tar.gz
  cd nettle-2.7
  
  ./configure --prefix=/opt/
  
  make &amp;&amp; make install
  
  cd ..
  </code></pre>
  
  <p>Install the latest GnuTLS, this version comes with a fix of security flaw:</p>
  
  <pre><code>wget ftp://ftp.gnutls.org/gcrypt/gnutls/v3.2/gnutls-3.2.12.tar.xz
  tar xvf gnutls-3.2.12.tar.xz
  cd gnutls-3.2.12
  export LD_LIBRARY_PATH=/opt/lib/:/opt/lib64/
  NETTLE_CFLAGS="-I/opt/include/" NETTLE_LIBS="-L/opt/lib64/ -lnettle" HOGWEED_CFLAGS="-I/opt/include" HOGWEED_LIBS="-L/opt/lib64/ -lhogweed" 
  
  ./configure --prefix=/opt/
  
  make &amp;&amp; make install
  
  cd ..
  </code></pre>
  
  <p>Install the Latest LibNL:</p>
  
  <pre><code>wget http://www.carisma.slowglass.com/~tgr/libnl/files/libnl-3.2.24.tar.gz
  tar xvf libnl-3.2.24.tar.gz
  cd libnl-3.2.24
  
  ./configure --prefix=/opt/
  
  make &amp;&amp; make install
  
  cd ..
  </code></pre>
  
  <p>Install Ocserv</p>
  
  <p>The latest version of ocserv is 0.8.0[1], if you want a git version, you might need to compile a recent version of automake and autoconf.</p>
  
  <pre><code>wget ftp://ftp.infradead.org/pub/ocserv/ocserv-0.8.0.tar.xz
  tar xvf ocserv-0.8.0.tar.xz
  cd ocserv-0.8.0
  export LIBGNUTLS_CFLAGS="-I/opt/include/" LIBGNUTLS_LIBS="-L/opt/lib/ -lgnutls" LIBNL3_CFLAGS="-I/opt/include" LIBNL3_LIBS="-L/opt/lib/ -lnl-3 -lnl-route-3" 
  
  ./configure --prefix=/opt/
  
  make &amp;&amp; make install
  </code></pre>
  
  <p>When I run <code>certtool --generate-privkey --outfile ca-key.pem</code> , I encounter the following error:</p>
  
  <pre><code>[root@arx ~]# certtool --generate-privkey --outfile ca-key.pem
  
  certtool: relocation error: certtool: symbol gnutls_srp_3072_group_prime, version GNUTLS_3_0_0 not defined in file libgnutls.so.28 with link time reference
  
  [root@arx ~]#
  </code></pre>
  
  <p>How to fix the error?</p>
  
  <p>Thanks.</p>
  
  <p>PS: the os in my linux vps is centos 7. In centos 6, I didn't encounter the error above.</p>