root@zentyal2:~# iptables -t nat -A PREROUTING -p tcp --dport 8080 -j DNAT --to-destination 10.30.105.212:8080
root@zentyal2:~# iptables -t nat -A POSTROUTING -j MASQUERADE
iptables: No chain/target/match by that name.

host:~# lsmod | egrep "xt_tcpudp|ip_conntrack|xt_state"
xt_tcpudp               2319  31 
xt_state                1303  54 
nf_conntrack           46563  10 nf_nat_irc,nf_nat_ftp,iptable_nat,nf_nat,xt_helper,xt_state,xt_conntrack,nf_conntrack_irc,nf_conntrack_ftp,nf_conntrack_ipv4
x_tables               13117  21 ip6t_REJECT,ip6_tables,xt_tcpudp,ipt_REDIRECT,iptable_nat,xt_helper,xt_state,xt_conntrack,xt_length,ipt_LOG,xt_hl,xt_tcpmss,xt_TCPMSS,ipt_REJECT,xt_DSCP,xt_dscp,xt_multiport,xt_limit,ip_tables,xt_MARK,xt_mark