Failed to submit job via FME Server Proxy when Core cannot communicate with Load Balancer

Question

How can I run jobs when my FME Server Core cannot send traffic to my Load Balancer directly?

Situation

 FME Server can be configured with a proxy server to enable the Web Application/Core/Engines to send outgoing traffic. However, the FME Services that are used to submit jobs were designed to remain internal so are not accounted for in this proxy configuration. In some installations, your Load Balancer may have the ability to send traffic to the core, but the core may not be permitted to send traffic back to the Load Balancer, in this scenario you will be unable to submit jobs via the run workspace page. 

Answer

The file ‘hosts’ is an operating system file that maps hostnames to IP addresses. For each core machine, add a line in the host file mapping the hostname of the Load Balancer to the current machine. The mapping consists of two values “127.0.0.1” which will reference the local machine and the name of the load balancer.  This entry will allow the calls needed to submit a service (run a job) to stay local to the machine. On a  Windows OS this file can be found at C:\Windows\System32\drivers\etc\hosts, for Linux it is /etc/hosts.

Example line to add to hosts file:

127.0.0.1        MyLoadBalancerName