So I propose to change the two lines to:
iptables -n -L INPUT | grep -q sshguard || iptables -w -I INPUT -j sshguard 2> /dev/null ip6tables -n -L INPUT | grep -q sshguard || ip6tables -w -I INPUT -j sshguard 2> /dev/null
I think one more optimization is needed. By adding the '-n' option,
reverse DNS lookups are prevented. Without this option, (re-)starting
the daemon may take a very long time.
