When isolating a slave (backup) network from the other nodes in the topology, slave becomes live after a while. We are using IPTABLES command in the test scenario.

test1:
iptables -A INPUT -p tcp --dport 61616 -j DROP
iptables -A OUTPUT -p tcp --dport 61616 -j DROP
iptables -A OUTPUT -p udp --dport 9876 -j DROP
iptables -A INPUT -p udp --dport 9876 -j DROP

test2:
iptables -A INPUT -p tcp --dport 61616 -j REJECT
iptables -A OUTPUT -p tcp --dport 61616 -j REJECT
iptables -A OUTPUT -p udp --dport 9876 -j REJECT
iptables -A INPUT -p udp --dport 9876 -j REJECT

If a slave is isolated it should stay passive to avoid split brains.