I got here because I was getting errors from my one and only server, using collectd and Splunk App for Infrastructure. The global SSL needs to be checked. If not, you will get the SSL error mentioned. Then, on the host running collectd, you need to ensule that the write_splunk stanza says "ssl true" in /etc/collectd.conf. If it says false, you'll see the following error: write splunk plugin: curl_easy_perform failed to connect to your_indexer_host:8088 with status 56: Failure when receiving data from the peer So, at this day and age (Splunk 7.3.3 with Universal Forwarder 8.0.1 on my client, and Splunk App for Infrastructure 2.1.0, ensure that the /etc/collectd.conf is correct, and that Globally, you have SSL checked (go to Settings-> Data, and hit the Global Settings box in the upper right hand corner).. ... View more

The app (on the search head) will help generate a script that will assist in the collectd installation... ... View more