Active Checks from dmz to LAN not working

[rolfrolf]

Hey Guys hope anyone can help me.
i got a Zabbix Proxy in our DMZ so it is available for our costumers and the server is not reachable from the Internet.
Now the passive checks are working perfect but the active checks always say: active check configuration recieved from ... ZBX_TCP_READ() timed out
when i put the proxy in our lan the active checks are also working perfectly.
i tried telnet from the proxy to the agents and from the opposite side and everything is reachable.

hope anyone has an idea on what i could try.
thanks in advance

[Hamardaban]

Carefully consider the full scheme of interaction agent<->proxy<->server in case of active and passive checks. Note that when active checks first a check list request from agent to proxy to port 10051

[AvaTTaR]

Some problem with firewall configuration test connection from proxy to server via telnet on port 10051, I have same scheme on DMZ and it works perfectly.

[rolfrolf]

tested everything and everything works fine
but i still get this error
could you maybe send me your conf files? maybe im missing something

[Nguyen Trang]

If your network has no problem, maybe your timeout too little. Try increasing the value of Timeout in the configuration file on the client. eg: Timeout=25

[rolfrolf]

have already tried that and nothing has changed

[Nguyen Trang]

I had the same problem. A passive check is Ok, but the Active check is not working.

You can try my configuration (disabled firewall and SELinux) -> restart service

Server:
ListenPort=10051
LogType=file
LogFile=/var/log/zabbix/zabbix_server.log
LogFileSize=1
DebugLevel=3
PidFile=/var/run/zabbix/zabbix_server.pid
SocketDir=/var/run/zabbix
DBHost=localhost
DBName=zabbix
DBUser=zabbix
DBPassword=**
StartPollers=5
StartPollersUnreachable=1
StartTrappers=5
StartPingers=1
StartDiscoverers=1
StartHTTPPollers=1
StartSNMPTrapper=1
ListenIP=0.0.0.0
Timeout=4
AlertScriptsPath=/usr/lib/zabbix/alertscripts
ExternalScripts=/usr/lib/zabbix/externalscripts
LogSlowQueries=3000
StatsAllowedIP=0.0.0.0/0

Agent:
PidFile=/var/run/zabbix/zabbix_agentd.pid
LogType=file
LogFile=/var/log/zabbix/zabbix_agentd.log
LogFileSize=0
EnableRemoteCommands=1
Server=::/0
ServerActive=192.168.40.128
Hostname=kvm31
Timeout=30
Include=/etc/zabbix/zabbix_agentd.d/*.conf

=> Check service

[root@zabbix-server ~]# systemctl status firewalld
Active: inactive (dead)
[root@zabbix-server ~]# sestatus
SELinux status: disabled

[root@zabbix-server ~]# netstat -taun | grep 10051
tcp 0 0 0.0.0.0:10051 0.0.0.0:* LISTEN