How to enable syslog forwarding from Isilon OneFS on Custom Port except UDP 514?

I have tried below in the /etc/mcp/override/syslog.conf

auth.*    @IP:1515

!audit_conf

*.*    @IP:1515

!audit_protocol

*.*    @IP:1515

!*

But I am still not receiving any syslogs. I have tried it on isilon OneFS v8.0.0.1 and v8.1.0.0.

Do I need to enable the port or disable the firewall?

NOTE: If I remove the colon and port then it is forwarding on the default UDP 514 port.

Thanks,
Pratik