Why I cannot find any udp port listening on my RHEL 7 server?

Issue

• I could not find any udp 514 port running when I issue the command ss -an | grep udp. I was configuring syslog-ng to listen on both tcp and udp port 514..

Instead , I only see the following:

tcp    UNCONN     0      0           1.1.1.1:514                   *:*
tcp    LISTEN     0      128         1.1.1.1:514                   *:*