My situation is like this:
Server with multiple network cards where BOINC is installed. Server NIC A has Internet connection available 24/h, only for server, NIC's B through F operates different VLANS witho NO Internet connection available. I will not allow any direct Internet connection to other VLAN's (it's my policy), but i've got advanced routing configured, so I can reach each BOINC client at any VLAN from my server.

Now the question is - is there any future, that can provide ul/dl WU's through my server? I can easily connect to remote clients, but they are using their local network settings (no Internet connection). Can BOINC Manager be some kind of WU's proxy for remote clients? Or maybe there is another solution.

Neither BOINC client or Manager have a feature that would allow them to work as a proxy for another client.

If it fits your policy you could install a real proxy on the server and then tell BOINC clients to use that proxy.

BOINC projects don't change their addresses all that often so other option is to route only traffic to project servers through your server.

Well, actualy i have proxy atm and clients are Internet connected through it (scheduler), but I don't like this solution and i tought there is a way to use BOINC Manager only. Thanks anyway.