Update :  It was effectively a misconfiguration of the network.  I haven't found a solution for this problem, so I worked around by making an instance of splunk enterprise in a docker container instead of a VM, and now I can see my docker's logs on Splunk enterprise. Traceroute showed me that sending packets from the container to the VM doesn't work. In the other way, it's functioning correctly. (I tried this after flushing all iptables rules and verifying that there wasn't any firewalld service activated.)   Thank you all for your help !   ... View more