N900 lan to lan FW

[scruffidog]

is there any way for me to limit a lan machine access to other lan resources ?

I was trying in the firewall section to create a rule that has a src and dst address pointing to the LAN. Unfortunately it won't save, the error stating that src and dst cannot be the same.

[TonyPh12345]

No, because the filtering is only done at the router level (or "Layer 3" network address).   The switchports aren't subject to filtering because they're switch ports (Layer 2 network), not router ports.