I have an x86 network router which has eth0-eth5 total of six ports. My ISP provides Internet on VLAN 500 and VOIP on VLAN 600 on the wan port and my ont port is connected with eth0. From my router an IP phone will be connected with eth1 and another 4 ports will be used for the LAN user will be connected. Now what will be my network configuration and the iptables rules that are needed there for the IP phone to allow VOIP communication?
The typical setup is to bridge the phone to the ONT on VLAN 600. The ISP will manage all DHCP etc of the phone. There is no routing of the phone network in the router. The firewall will have no effect, so there is no need to configure any firewall rules.
Your config file is in the old syntax. In the new syntax, bridges are declared separately.
option name 'br-voip'
option type 'bridge'
list ports 'eth0.600'
list ports 'eth1'
config interface 'voip'
option device 'br-voip'
option proto 'none'
If the phone expects tagged packets as if it were plugged into the ONT directly, use eth1.600.