Zabbix Agent 5.2.4 on Windows 2019

[igalsc]

Hey guys,

I have a Zabbix 5.2.2 running on Ubuntu, in AWS with agent passive configured. The server name (and hostname on Ubuntu server) are zabbix.rest_of_FQDN.here
In my zabbix_agentd.conf on the Windows machine, as well in AWS, behind Classic Load Balancer, I have this as config:

LogFile=C:\Program Files\Zabbix Agent\zabbix_agentd.log
LogFileSize=10
DebugLevel=3
Server=zabbix.rest_of_FQDN.here
ListenPort=10050
#ServerActive=zabbix.rest_of_FQDN.here
#Hostname=SOME-HOST-NAME
Timeout=10

In the agent log I see

 failed to accept an incoming connection: connection from "10.0.2.231" rejected, allowed hosts: "zabbix.rest_of_FQDN.here"

The 10.0.2.231 is my ELB IP address, because my server's internal IP is in the 10.0.2.x network.
Since the Windows host is in the Auto Scaling group, I cannot and do not wish to put all the internal networks in the "Server= " in the config file.
I can't understand why the actual hostname is not being passed to the agent. Hope you might help me, as I'm opening a support case with AWS as well.

Thanks,
Igal

[igalsc]

Ok, I had figured it out with AWS support, will post the solution here, in case someone else is having the same issue.
Since the communication is over TCP port, the LB does not pass the actual requester's IP, but sends its own. You have a way to see the internal IPs the LB uses in the EC2 console by using the Network Interfaces, and then searching for the LB name.
So, I updated the

Server=10.0.2.231,10.0.1.108

and it's working now in the passive mode.