Samba supports machines with multiple network interfaces. If you have multiple interfaces, you will need to use the interfaces option in smb.conf to configure them. For example, the machine you are working with has 4 network interfaces; eth0, eth1, eth2, eth3 and only interfaces eth1 and eth4 should be used by Samba. In this case, the following smb.conf file entries would permit that intent:

The bind interfaces only = Yes is necessary to exclude TCP/IP session services (ports 135, 139, and 445) over the interfaces that are not specified. Please be aware that nmbd will listen for incoming UDP port 137 packets on the unlisted interfaces, but it will not answer them. It will, however, send its broadcast packets over the unlisted interfaces. Total isolation of ethernet interface requires the use of a firewall to block ports 137 and 138 (UDP), and ports 135, 139, and 445 (TCP) on all network interfaces that must not be able to access the Samba server.