Also I was recently shown an alternative way to add addresses to interfaces which may become the recommended way:
iface eth0 inet manual
up ip link set dev $IFACE up
up ip address add dev $IFACE brd + x.x.x.x/26
up ip address add dev $IFACE brd + 192.168.155.20/24
up ip address add dev $IFACE brd + 192.168.155.21/24
up ip address add dev $IFACE brd + 192.168.155.211/24
down ip address flush dev $IFACE
down ip link set dev $IFACE down
This leverages iproute2 and is probably the more straightforward way to do complex setups. Note that I haven't tested this, it was just an idea somebody else showed me.
Also I was recently shown an alternative way to add addresses to interfaces which may become the recommended way:
iface eth0 inet manual
up ip link set dev $IFACE up
up ip address add dev $IFACE brd + x.x.x.x/26
up ip address add dev $IFACE brd + 192.168.155.20/24
up ip address add dev $IFACE brd + 192.168.155.21/24
up ip address add dev $IFACE brd + 192.168.155.211/24
down ip address flush dev $IFACE
down ip link set dev $IFACE down
This leverages iproute2 and is probably the more straightforward way to do complex setups. Note that I haven't tested this, it was just an idea somebody else showed me.