IPv6 in Zabbix active agent

[boromartin]

Hi,

Zabbix noob here. I've been trying to get active agent wotking over IPv6 for the apst few days, but I havent been able to get them to communicate. I am pretty sure that I am doing somtehing incorrectly, but unfotunately, i haven't been able to find many guides on such metters.

At the moment, I have four identical Debian VMs each running an Active Agent, version 4.0.4, all working via IPv4 with a similar VM, running server 4.4.1. According to the logs, everything has IPv6 enabled. TLS is either set to unencrypted, or left commented.
I've been trying to move one of the clients to IPv6 using the same logic as when I was configuring them with IPv4, but I haven't had much success.

Anyone has any advice?
Thanks in advance.

[tim.mooney]

Make certain it's not a firewall issue on your Zabbix server. Unless you're running a very recent server that's using nftables for the firewall (where IPv6 and IPv4 firewalls are potentially combined into one), remember that opening ports in an iptables-based firewall doesn't automatically open them in ip6tables.

Along with that, make certain that your Zabbix server is actually listening on both ipv4 and ipv6. It should be if your server has IPv6 enabled, but it's something you should at least verify.

Your combination of agent versions and server version should work, but also please keep in mind that later versions in a particular release series tend to have more bugs fixed. You may want to try upgrading at least one agent to 4.0.18 or 4.0.19 if it's available, and see if that makes any difference.

[boromartin]

So, I have a few updates.
I "turned off" both iptables and ip6tables by flushing all chains and setting everything to accept.
I updated the agent to version 4.4.8.
Also, i checked confirmed, that both ports 10050 and 10051 are set to LISTEN on both IPv4 and IPv6 .

But what really seems to be the issue is, that the server is still attempting to contact agents from it's IPv4 address, since zabbix_agentd.log is filled with this:
"8349:20200426:001540.312 failed to accept an incoming connection: connection from "[IPv4 server address]" rejected, allowed hosts: "127.0.0.1, [IPv6 server address] "

[tim.mooney]

Sorry, now I'm confused.

Are you using both passive and active items? If your Zabbix server is contacting your agent and being refused, that's likely part of a passive check.

Did you set ServerActive in your zabbix_agentd.conf file, and are the items that are assigned to your client/agent host set to "Type: Zabbix agent (active)"?