How to use eth2 and block ports

The UTM firewall blocks everything by default.  In any case, DHCP broadcasts don't travel outside an Ethernet segment without a relay - a firewall rule alone won't facilitate the traversal of the UTM by DHCP broadcasts.

Cheers - Bob

At this time are in the same Ethernet segment.

UTM -> ETH0 -> SWITCH

On Switch i have an access point (Brdige mode) link to another access point (Bridge mode) at my home.
At my home i have an Adsl with DHCP in the same lan.

In fact if i connect my laptop to office switch, sometimes i take IP from home DHCP and sometimes to Office one.

You know what i mean?
I want to surf to my office network from home but DHCP must separate, can't travel to bridge.

You shouldn't have your home and office bridged, Marco.  Your idea of connecting the wireless bridge to a different interface is the right thing to do.

Cheers - Bob

Home and Office are in Bridge because i need to work from home and use office network shares, i could buy another SG 105 and create a VPN site to site but i have only one.
So, i can connect wireless bridge to a different interface (like ETH2) but how can i block DHCP? How can set my Firewall to block 67/68  UDP from/to ETH2 port? 
I can create an Ethernet Bridge with ETH0(lan) and ETH2(Home) and then make them become one network, it works but that's not good yet. 

Conceptually, Marco, there's no difference between a site-to-site VPN and connecting your wireless bridge to eth2.  I'm giving you the correct solution, but I don't understand what more I need to explain.

Cheers - Bob

I understand Bob, connection office - home works, i just need to Block Dhcp through Bridge. I need to know (if possible) if i can block any ports on specific interface like Eth2.

Marco, I think we're getting confused by the term "wireless bridge." This is no different than having an Ethernet cable connecting eth2 to your home network.  There should be no "bridge" configured on the UTM, so no DHCP should pass through the UTM in either direction.

Cheers - Bob