Currently linux-virt-grsec-3.4.5-r2 does not have TARPIT support:

# iptables -A tarpit -p tcp -j TARPIT
iptables: No chain/target/match by that name.

AWall needs it by default.

Thank you

(from redmine: issue id 1299, created on 2012-08-03, closed on 2012-08-17)