Zabbix server and client with 2 IP-addresses

Question

Zabbix server-5, Debian 10.4. Data from remote hosts are collected via Zabbix Proxy ( zbp1 ). Scheme of connection is on image below.

Remote host connects via his ISP #1 to main office using VPN-servers. On Main office there're two VPN servers (located on two separate ISPs), named VPN #1 and VPN #2. Each server uses it's own subnet, i.e VPN #1: 10.30.0.0/16, VPN #2: 10.40.0.0/16.

On Zabbix server host is created manually, two interfaces are defined (Type: agent, ip1: 10.30.0.10, ip2: 10.40.0.10). Strandard Template_OS_Linux is connected to host. Image of host creation is below.

When host is connected to VPN #1 via ISP #2.1 - information is gathered by Zabbix server (because in host definition IP-address of this subnet is declared first). But, when host switches to another VPN-server (VPN #2 and ISP #2.2) Zabbix server says, that host is unreachable. So, no data is collecting.

How can I tell Zabbix server, that my remote host connects to two separate remote VPN-servers and Zabbix-server has to gather information from one interface of two, that is active now? And if all two interfaces are unreachable - then it has to report problems.

Creation of two separate hosts on each subnet is not a good idea...

Joining VPN #1 and VPN #2 into one subnet is not possible now.

Answer 1

I imagine having one server taking different IP addresses depending if primary ISP is up or not poses multiple issues - not only to zabbix monitoring.

My advice is to solve the problem with one VPN server with 2 NICs - serving clients coming from both ISPs with one IP subnet.

Alternatively solving clients with changing IP with IP NAT - whenever new client connects - have firewall do a dynamic NAT for client's IP so for anyone "inside" the client would have still the same IP address.

No idea whenever any of that is possible at your setup - here's the final suggestion solving only the monitoring - not the network:

Switch to active agent configuration - in this way the zabbix server/proxy does not use the client configured IP address as client initiates the connection - you can have the client IP to be "127.0.0.1" - it does not matter (for active zabbix agent).