<a name="TLSShmcacheUndefinedSymbol">
<font color=red>Question</font>: I am trying to use
<code>mod_tls_shmcache</code> as a shared module, but my <code>proftpd</code>
server fails to start up, failing with this error:
<pre>
  proftpd: symbol lookup error: /usr/local/libexec/mod_tls_shmcache.so: undefined symbol: tls_sess_cache_register
</pre>
<font color=blue>Answer</font>: This happens when your configuration is
loading the <code>mod_tls_shmcache</code> module <i>before</i> the
<code>mod_tls</code> has be