50% ping loss to Google after change of network gateway

[hannes.palmquist]

I have a host setup with DNS name www.google.com to monitor internet connectivity according to the image below.



Ping loss 2days:

Ping responsetime 2 days:


Ping 2 days:


Normally this reports steady 0% ping loss.

Recently we changed default gateway on the network that the zabbix server is connected to. And this monitor now shows 50% ping loss steady. The other two monitors ICMP ping and ICMP responsetime does not seem to be affected by this, they show UP and ~2ms steady.

I've tested to run fping from the zabbix terminal to www.google.com and I get 0% ping loss. This is the only indication of ping loss I can find, -all- other ICMP ping loss report 0% ping loss within the environment. This includes several subnets via the router. We also have other internet availability hosts via zabbix proxies showing 0% ping loss.

So in summery it seems that -only- the ICMP ping loss monitor from the zabbix server it self get ICMP ping loss 50% to www.google.com. Which leads me to belive that there must be some config somewhere within zabbix server that I need to update, ie default gateway or something. The old gateway is offline so the zabbix terminal fping tests takes the correct route through the new gateway.

The zabbix server is HyperV appliance with DHCP assigned IP (reserved/static mapping from the DHCP). (I've rebooted the zabbix server)

Any ideas for what to look for on the zabbix server?

Kind regards Hannes

[hannes.palmquist]

I've managed isolate the issue alittle bit and I think it might be related to ipv6.

I've had the host configured for DNS name www.google.com, when I change to a IPv4 address the ping loss dropped to 0%. Changing back to dns name it returned to 50%. Doing a nslookup of www.google.com ofcourse returnes a A and a AAAA record and probably zabbix pings both. ICMP for Ipv6 is not configured in our environment so that fails so most likely this is the cause of the exact 50% ping loss.

So this leads me to another question, how can I configure zabbix to only resolve ipv4 addresses for hosts? I can not find any parameters for ip version modes on the icmppingloss keys.

[rbohlmann]

I had also encountered the same 50% ICMP Loss issue for google.com on my system and temporarily fixed it by using the IP Address instead of the DNS name. Were you able to find the root cause and correct it so you could go back to using the DNS name?