Two DHCP Servers in two different networks

I’ve got two DHCP Servers in two different networks, but when I trie to run check_dhcp only responds one, concretely the one which is in my network.

Solution?

Thank You

Add some flags onto the check_dhcp command.

check_dhcp:
Usage: check_dhcp -s serverip] -r requestedip] -t timeout] -i interface]