I have configured the setup mentioned in following drawing with Cisco 3650 core switch and two Cisco 2960 access switches. After configuring ip route 0.0.0.0 0.0.0.0 192.168.30.254 on core switch, vlan 30 is able to access internet while other vlans couldn't. Could someone please say what seems to be the issue preventing vlan 10,20 from accessing internet?
DHCP server and inter-vlan routing is working.
P.S - Sorry for my poor English
Where is the default gateway configured for all the VLANs? I presume the DG in Core switch right? If this is the case, please use a different VLAN and subnet between the core switch and the FW. So all the traffic from VLANs 10,20,30 will hit the core switch (L2) and then from there will be routed to the firewall (L3)
The FW will be perfroming the NAT, so make sure that FW is aware of vlan 10,20 and as the routes back towards the core switch also it has the corect NAT rules for those other two subnets.