Getting "cannot send list of active checks" to servers not listed in Zabbix

[linuxgurugamer]

We have about 150 servers currently reporting to a Zabbix 3.4 server.

I'm in the process of setting up a new infrastructure, with a master Zabbix server in AWS and multiple satellite servers. For now, I have the new Zabbix 4.0 server set up and a single satellite server running the Zabbix proxy 4.0 in our current location.
Once I got past the issues of poor documentation regarding setting up the Postgresql databases (that's another story), I have the two servers working. I've also added one additional server to the new master, using the installed config. The agent config on the old server was modified to add both the new servers to the Servers and ServerActive (and the agent was restarted)

What's now happening is that I'm seeing the following in the zabbix_proxy.log file (hostnames have been scrubbed):

32436:20181211:154456.440 cannot send list of active checks to "192.168.100.164": host [***] not found
32438:20181211:154456.519 cannot send list of active checks to "192.168.150.7": host [***] not found
32433:20181211:154456.720 cannot send list of active checks to "192.168.100.202": host [***] not found
32442:20181211:154457.278 cannot send list of active checks to "192.168.100.230": host [***] not found
32382:20181211:154457.560 cannot send list of active checks to "192.168.100.155": host [***] not found
32381:20181211:154459.220 cannot send list of active checks to "192.168.100.94": host [***] not found
32381:20181211:154459.711 cannot send list of active checks to "192.168.150.34": host [***] not found
32430:20181211:154500.259 cannot send list of active checks to "192.168.100.206": host [***] not found
32430:20181211:154518.390 cannot send list of active checks to "192.168.150.42": host [***] not found

Somehow, the proxy has gotten the list of all the servers in the old Zabbix 3.4 server, and is trying to communicate with them. What's really interesting is that the one server which was configured to work with both Zabbix systems is not listed, while the satellite server IS listed in these messages

It seems to be harmless, but I'd like to know how the zabbix proxy got all this information.
The Zabbix 4 server is a standard install, no special configurations except for adding the proxy in the Administration->Proxies, and both the proxy and the other server in the Configuration->Hosts

Any ideas?

Thanks in advance

JBB

[dimir]

Looks like the same proxy is used for both the old and new server.

[linuxgurugamer]

Old server was not proxied. We are moving to a proxy based setup, this is part of the migration testing.
As of now, I've been able to migrate the database, by doing a pgdump on the old zabbix server, loading it using psql into the new zabbix server, and then going a mass update to change all the servers from a direct monitor to using a proxy.

Oh, and I think I just figured it out. As part of the migration, I updated all the zabbix_agentd.conf files to know about the proxy. I think that all the agents are now querying the proxy looking for their list of active checks, and we don't really use them.

[dimir]

Oh, that makes sense. If you are not using Active checks you may change agents to the passive mode by setting ProxyMode=1 in agents configuration file.