No active checks is sending checks to hosts that don't exist in our zabbix instance

[NewUser1]

Good Afternoon,

I am seeing these errors in the logs, we are not using IPv6. Also all of these hosts at one point might have been clients of our Zabbix server

3229:20250108:131921.321 /usr/bin/fping6: can't create socket (must run as root?)
3224:20250108:131921.707 cannot send list of active checks to "10.1.6.1": host [HOSTNAME1] not found
3226:20250108:131923.223 cannot send list of active checks to "10.1.6.2": host [HOSTNAME2] not found
3222:20250108:131924.853 cannot send list of active checks to "10.1.2.3": host [HOSTNAME3] not found
3222:20250108:131926.716 cannot send list of active checks to "10.1.6.1": host [HOSTNAME1] not found

How do I fix these events in the log file?

EDIT: I wanted to add that some hosts are already in Zabbix and and I can see their Availability is green. But there are events generating for those same hosts in the zabbix logs. Could it be because of the ipv6?

[cyber]

I dont think that fping6 line and those others are related. "Cannot send list..." just informs, that this host has turned to server to get checks, but it is not defined in Zabbix yet. If you create those HOSTNAMEX hosts, this should go away...

from docs..

Fping6Location
The location of fping6. Make sure that the fping6 binary has root ownership and the SUID flag set. Make empty ("Fping6Location=") if your fping utility is capable to process IPv6 addresses.
Default: /usr/sbin/fping6

Verify that those requirements are set...

[NewUser1]

Got it! Thank you cyber. I will make those host names but is there a way to remove them because he is some don't exist with the names it is trying to look for.

[cyber]

It looks like somewhere there are some servers using that config and asking for checks, if those are not needed, then shut them down.. Or at least disable agent on them.

[NewUser1]

Interesting one of the hosts showing up in the logs is showing up with the correct IP but we converted to DNS so we are using DNS for our interface. The name in the logs is in CAPS but the name in the UI is with lowercase letters. IDK I would think that the agent on those hosts should be able to update and know to use the DNS instead. How do I fix this problem without turning off the hosts?