It would be nice to have an option to specify a network interface name in the following zabbix agent checks:
net.tcp.port[<ip>,port]
net.tcp.service[service,<ip>,<port>]
net.tcp.service.perf[service,<ip>,<port>]

Having this option, one could setup a simple template for identical services, listening on the same interface on different hosts, without specifying an IP as a user macro on the host.

Example: net.tcp.service[service,<ip>,<port>,interface]

Use case:
My service is listening on
hostA, eth0, IP 10.0.0.1, port 443
hostB, eth0, IP 10.0.0.2, port 443

To monitor the service, one would create a template with key net.tcp.service[https,,443,eth0] (ip field is empty, interface specified) and attach it to hostA and hostB.

Instead of checking the service on 172.0.0.1, the agent will obtain from the OS the default (primary) IP of the interface specified and perform the check.

I'm aware that I could use the {HOST.IP1} macro, but it will not work if the host is defined with agent interface with IP 0.0.0.0 and 'connect to': DNS.