Minecraft Server 1.8.9 - Can't Connect [duplicate]

I have two newly set up Minecraft 1.8.9 servers. With both servers when I point my Pocket Edition clients to them I receive an "Unable to connect to world." message.

1) Debian 8
2) CentOS 7

[root@minecraft Downloads]# java -version
openjdk version "1.8.0_65"
OpenJDK Runtime Environment (build 1.8.0_65-b17)
OpenJDK 64-Bit Server VM (build 25.65-b01, mixed mode)

Both servers behaving the same way, I did a packet capture on each and can see UDP traffic reaches each them. And both servers respond with ICMP Port Unreachable. No surprise since the UDP port is not open I found. Minecraft server is only opening the TCP port...

[root@minecraft Downloads]# netstat -anp |grep 25565
tcp       0      0 0.0.0.0:25565           :::*                    LISTEN      21202/java

I looked through Minecraft's server.properties documentation and see nothing pertaining to the protocol being configurable, only the port.