Zabbix proxy -server communication not working

[Avalonit]

HI All, I have a problem that's buggin me for a week now so i decided to post it here to see if anyone can help.

Ok in subnet 1, 10.14.1.X I have a working zabbix server that talks to a couple of hosts with no problems.
some of the hosts are in subnet 2 : 172.18.2.X. and i decided to put a proxy there so i could monitor some more stuff..
There is a VPN tunnel between the 2 subnets and i can telnet from zabbix server to proxy over port 10051 and also the other way around.

So now there's a proxy running on 172.18.2.15. I've changed the hosts to talk to the proxy instead of the server directly.
In the proxy log i see complaints like 'cannot send list of active checks to [ip host]: host [name host] not found.
So i assume the host is talking to the proxy but proxy has no information about this host.
On the zabbix server i created the proxy,active with same name (case sensitive) and indeed, if i change the name of set is to passive i see complaints in the logs.

So everything seems to be fine except the proxy does not get the items / checks to send to the hosts and on zabbix server the agent for everything behind the proxy is unreachable.

Everything is version 2.4.4 and i even reinstalled everything to see if that would solve anything but it didn't.

Any suggestions are most welcome, thank you in advance for your time

[ingus.vilnis]

Hi,

There are two things to configure if you switch from server to proxy.
1. Set the specific hosts to be monitored by proxy in Zabbix web frontend.
2. Set Server and ServerActive parameters to IP of proxy in zabbix_agend.conf files for those hosts that will use the proxy.

Is everything fine with these basic things?

Also if you switch a host to be monitored by proxy in frontend, it may take some time for proxy to renew the configuration. (3600 seconds by default). therefore you might be getting some errors at the first time.

Best Regards,
Ingus

[Avalonit]

Hi Ingus

It turned out problem wasn't with zabbix.. I was running the proxy - server connection through a site 2 site VPN tunnel created by 2 Cisco ASA 5505 devices. All communication looked fine, as far as i could see, but the proxy never recieved the list of tasks.
After much trying and frustration i switched the configuration so communication went over the internet, not through the tunnel and things started working like imidiately.
So for some reason still unclear to me, a tunnel between cisco asa's does something weird to the data traffic.
I would really like to know why since it's a bit of a pain to have to open additional firewall ports and make configuration when you allready have a tunnel in place..

[antik]

Had similar issue with long-distance VPN connection. Solved temporarily with MTU change to 1400 on proxy eth0 interface.

auto eth0
iface eth0 inet static
	address xxx.5.111.222
	netmask 255.255.255.0
	gateway xxx.5.111.1
	mtu 1400

[kloczek]

There is a VPN tunnel between the 2 subnets and i can telnet from zabbix server to proxy over port 10051 and also the other way around.

Such direction of the communication (srv->prx) is using passive proxy.
Are you sure that your proxy i passive proxy? (Administration->Proxies mode column)