I have deployed Splunk on a CentOS machine and forwarder on Windows Server 2012 R2.
After installing the universal forwarder, the host is not showing up in
In CentOS what ar you using as local firewall firewall-cmd or iptables? Have created the rules to accept connection there?
In what? Please finish the question.
Is Splunk configured to listen on port 9997 (Settings->Forwarding and Receiving)?
Is the UF configured to send to Splunk?
Have you checked your firewall(s)?
nobody can help you if you don't answer questions