When configuring the syslog messages source IP as the loopback IP of the router but having enabled the mgmt_junos routing instance, the messages will source from the mgmt IP and not the loopback regardless of the config source IP being the lo0 IP.

user@router> show configuration system syslog

user * {

any emergency;

}

host X.X.X.X{

any info;

source-address X.X.X.X; <<<<<<<<

The source-address using (lo0) is in inet.0 and the communication is happening in mgmt_junos instance.

When management-instance is enabled, evnetd attempts to bind the configured source address with the mgmt_junos routing instance. This has been the behavior since management-instance was introduced.

In some cases customers have seen the same problem with reports of this in their logs:

"eventd: could not bind to address X.X.X.X: Can't assign requested address"

Using management-instance and syslog source-address as intended:

Use lo0 as the source address (default RI) WITHOUT the management-instance knob.

Use re0:mgmt-0 as the source address (mgmt_junos) WITH the management-instance knob.