Hi Peter, above is my understanding of what you're describing. Please correct me if I am wrong.
- You have defined two VLANs in the X450-G2
- You have configured each VLAN with a IP and enabled ipforwarding
- Host A can ping the VLAN interface IP addresses, however not Host B
If the above is what your topology looks like, it should work fine. Check the FDB on each VLAN to see if the MAC of the hosts has been learnt. I quickly set this up to double check, and the initial pings did not work until I had made an attempt to ping from each host. Once the MACs had been learnt, on each VLAN, the link worked just fine.
However, if the above is not your actual topology and you have multiple physical devices, you'll need to define routes that tell the IP interfaces on one host how to get the IPs on the other.