Message from <Zabbix Server IP> is missing header. Message ignored.

[afagund]

Hi,

My Zabbix server is having trouble to communicate with one of my clients.

On Zabbix server I see the following message when checking the availability of the client.

Get value from agent failed: connection closed during read

On the client, in the agent logs, I see the following.

Message from <Zabbix Server IP> is missing header. Message ignored.

I have tried to restart the agent and server services, but still same issue.

Does anyone have any ideias on how to resolve this?

Thanks!
Andre

[afagund]

Reinstalling the agente does not fix the issue.

[afagund]

Hope someone can help me on this. Still facing the issue. I have also tried to reboot Zabbix server, recreate the host and reinstall the agente, but problem still persists.

I have noticed that zabbix_get is able to retrieve information from the agent, but the server is not.

[afagund]

Problem fixed installing a new Zabbix server and exporting / importing database from the old server.

[Justin417]

Hello,
I'm having the same exact issue. I've never had this problem in the past 8 months of my Zabbix server running.

Server is running Ubuntu 16.04.3 LTS and client also running Ubuntu 16.04.3 LTS.

My zabbix_agentd.log shows:

404:20180207:222151.597 Message from 100.x.x.x is missing header. Message ignored.

By chance, is there any alternative to completely re-installing my server?

Thanks for reading.

[stalks]

Our CPanel server has updated Zabbix Agent to 4.0.0alpha3 and is now having the same issue.

[stalks]

Fixed this by uninstalling the YUM installed package and downloading 3.x latest RPM direct from Zabbix repo

[afagund]

Unfortunately I had to reinstall the server to fix this. But for me, it was a quick procedure. I took like 30 minutes to create a VM, reinstall Zabbix and restore the database. Hope you guys find a final solution for this. I also noticed the issue was not just with one client, I was facing the issue also adding new ones. Probably the ones working at the moment would face the same issue moving forward.

[freitaszbx]

Problem fixed here

I had this problem, but it was happening only with hosts monitored by proxies.

I had to upgrade my proxy to the version 4.0 alpha4.

Don't forget to delete the proxy data base after the update, and let the proxy4 create a new one.

Bye

[thesubmitter]

I just saw this on one of my machines might be a compatability bug between 3.4.x proxies/servers and 4.0 agents?

[ingus.vilnis]

It is not really a bug. Newer agents were never officially supported for older servers (although in many cases they worked with no problems). Now 4.0 agents do not support passive checks from older Zabbix servers.

Options:
1) Downgrade agent to match server
2) Upgrade server to 4.0
3) Configure the agent checks to active.

[akj]

It must be nice to be able to depend on an entirely homogeneous environment.

[kwoot]

I couldn't agree more. To me this is the first real Zabbix disappointment since I started using it in 1999 or so. Someone clearly has not heard of backwards compatibility.

[MarshyMarsh]

Downgrading the agent(From 4.x to 3.x) to match what was on the Zabbix server(3.x) did the trick. Someone had installed an agent version greater than what was present on the Zabbix server.