dhcrelay wont deliver packaged to DHCP Servers if I dont add the DHCP Server interface to the config

name: dhcrelay wont deliver packaged to DHCP Servers if I dont add the DHCP Server interface to the config
about: Redudant and unecesarry declaration

/usr/sbin/dhcrelay -4 -d --no-pid -i eth6 -i eth1 -i eth2 -i eth4 -a 10.1.40.3 10.1.40.4

eth6 is ONLY used to comunicate with DHCP Server, no DHCPCLIENTS will be on that interface but I am not able to delete that interface from config even when I spesify DHCP servers address, if I do so packages will not be forwarded.

DHCPCLIENT request comes only from -i eth1 -i eth2 -i eth4