Error message: Communication failed: [Errno 111] Connection refused
Output of “cmk --debug -vvn hostname”: (If it is a problem with checks or plugins)
socket.error: [Errno 111] Connection refused
Hi all,
my checkmk installation works fine in my local subnet. There are about 22 systems monitored successfully. Now I want to integrate a additional windows server. This server is reachable through a IPsec VPN. The agent is installed and when I try to connect the server from my local Windows 10 machine (same subnet as checkmk) with putty, the answer from the server is coming.
I added the server as host and try to discover the services, I got the Communication error. I also tried the diagnose tab and the ping worked, but in the agent section is still the communication error.
a tcpdump at the checkmk machine shows that only the icmp packets are sent and received. No communication with port 6556. The checkmk machine did not contact the server with the 6556 service.
Is there a setting i missed to enable the communication?
The checkmk monitoring machine is in subnet 1.
The server to be monitored is in subnet 2.
subnet 2 is reachable from subnet 1 through a ipsec VPN connection.
My windows workstation is also in subnet 1.
If I use putty with telnet at port 6556 from my workstation in subnet 1 and try to connect the server in subnet 2, I see the information that the server answers to me. Everything as it should.
→ the vpn is ok! Firewall is ok!
Making a connection test from the checkmk machine (subnet 1) to the server (subnet 2) the ping is working, but no conversation at port 6556.
Next test was to use tcpdump directly at the checkmk machine.
→ tcpdump -i any host (serverip)
Then start the connection test again.
I see only the ICMP packets, no 6556 packets. I changed the command to a ip address of a server in subnet 1 and I see a lot of 6556 packets.
→ -> the checkmk machine can reach the server in subnet 2 (ping is working)
→ -> the checkmk machine sends no 6556 packets to subnet 2.
Hi Ralf,
I’m not an CentOs specialist. I tried some routing and firewall settings with no luck.
The easiest way (for me) to solve it was to install a Ubuntu machine. The test with a telnet on that machine worked perfect. So I installed a fresh checkmk to it and restore my config. Thats it.
This topic was automatically closed 365 days after the last reply. New replies are no longer allowed. Contact an admin if you think this should be re-opened.