Problem configuring Zabbix Agent v2 with PSK on Debian streach

[Alex Stoica]

Hello,

Good morning, everyone!
I'm trying to configure Zabbix Agent v2 on a Debian Stretch Linux machine.



When trying to configure it with PSK settings, it returns the following error on the Zabbix web interface:

 “Get value from agent failed: TCP successful, cannot establish TLS to [[X.X.X.X]:10050]: SSL_connect() set result code to SSL_ERROR_SSL: file ../ssl/record/rec_layer_s3.c line 308 func ssl3_read_n: error:0A000126:SSL routines::unexpected eof while reading: TLS write fatal alert "decode error"
​

And in the logs of the Zabbix server:

1890:20231006:110745.053 Zabbix agent item "system.cpu.load[all,avg15]" on host " ExampleVM1" failed: first network error, wait for 15 seconds
1891:20231006:110800.146 Zabbix agent item "system.cpu.num" on host " ExampleVM1" failed: another network error, wait for 15 seconds
1891:20231006:110815.156 Zabbix agent item "vfs.fs.get" on host " ExampleVM1" failed: another network error, wait for 15 seconds
1891:20231006:110830.173 temporarily disabling Zabbix agent checks on host " ExampleVM1": interface unavailable​

Here's the explanation of the configuration:

Server=X.X.X.X (Zabbix Server)
ServerActive=X.X.X.X (Zabbix Server)
Hostname=ExampleVM1
TLSConnect=psk
TLSAccept=psk
TLSPSKIdentity=Key generated randomly (Example: dasgfrtwe234AVC3)
TLSPSKFile=/etc/zabbix/psk.file (The file created with the PSK code has a chmod +777)

After confirming that it worked on Windows, I performed the aforementioned configuration on Linux, encountering the same errors mentioned earlier.
I saw some links on the Zabbix forum indicating that the PSKIdentity must be different from other machines (I also tested this without success, reproducing the same error).

Here are the links I followed, but without success:

https://www.zabbix.com/forum/zabbix-troubleshooting-and-problems/460922-zabbix-agent-2-v6-4-0-tls-write-fatal-alert-decode-error

https://www.zabbix.com/forum/zabbix-troubleshooting-and-problems/437893-zabbix-with-psk-encryption-tls-write-fatal-alert-illegal-parameter

Any assistance or insights into these issues would be greatly appreciated. Thank you in advance for your help!