Splunk and Ubuntu

Hello all, trying to get Home Monitor running on a Splunk install but I'm not getting any data indexed.

Splunk is installed in an Ubuntu 14.04 VM in ESXi, router is an Asus RT-AC68U set to send sys logs to the Ubuntu machine's IP address. Home Monitor and Maps app installed in Splunk, data input set for UDP 514.

I have a feeling its a firewall to blame, but it looks like the default IP tables are not set to block anything. Grasping at straws here...