VLAN 112 on the switch attached to a firewall interface in the same VLAN
Make sure VLAN 112 is tagged towards the ESXi and allowed on all required ports.
If in doubt, check whether the switch has associated the VM's MAC address with both the ESXi port and the desired VLAN.
Whether you tag VLAN 112 towards the firewall depends on the firewall's port configuration. Again, check the switch's MAC table to be sure.
If DHCP fails, temporarily try a static configuration. If that works, your DHCP service is off or there's a filter in between (DHCP snooping?).
If the static configuration doesn't work either but MAC/port/VLAN associations look fine, ping the firewall and look for its MAC in the ARP table. If ARP works there's an IP filter in between.
if i plug a raspberry pi instead of ESXi host to a switch port, it gets an IP inside that VLAN 112 subnet.
That looks like you're not tagging the VLAN towards the host. If you enter a VLAN ID on the vSwitch port group, that means tagged.
From comment:
esxi is a guest machine on a vmware workstation (windows pc) with a bridged network.
Ugh - OK... That changes everything.
With VMware workstation, VLAN tagging is likely not working at all - without the ESXi knowing that. So, outgoing frames don't get tagged but incoming, untagged frames are never forwarded into the original port group. Pretty much explains the effects you're seeing. Should also reflect on the switch's MAC table.
And there might be no way to get it working. Best bet with Windows is a vendor tool for your NIC, create virtual NICs and connect those to the ESXi individually - do not use VLAN ID/tagging on the ESXi then. Windows doesn't do tagging and you can't force it retroactively by running a virtual ESXi.
