I'm not sure how to pass through the DHCP or what to do on the Aruba VLAN for DHCP. If I plug something in to port 13 or 14 it still gets a 10.10.1.x address and not a 10.10.10.x address. I untagged ports 13 and 14 from the default VLAN. I've set the default gateway for the VLAN to 10.10.10.1 and left IP configuration as disabled. I've tagged ports 13, 14 and port 50 on VLAN 10. Using the Aruba web GUI I've created a matching VLAN with ID 10. Any ethernet device I plug in to any port 1-48 gets a 10.10.1.x address and can access the internet. I've factory reset an Aruba 2530 and connected the Aruba switch port 50 to my Fortigate interface with the VLAN. I've added a VLAN to it with an interface address of 10.10.10.1/24 and DHCP of 10.10.10.2/24.

I have an interface on the Fortigate with an interface address of 10.10.1.1/24 and DHCP of 10.10.1.2/24 I am very sorry bringing this here but I am new to this and have tried a lot of Youtube videos and trawled through Fortinet threads and Aruba ones here (as well as Spiceworks) to try and find some pointers.

Fortigate 600d