ipv6 forward rule after prerouting - Howto

[Daniel Huhardeaux <tech@tootai.net>]

Hello,

I setup prerouting rules with maps like

chain prerouting {
    type nat hook prerouting priority 0; policy accept;
    iif "ens3" ip6 saddr . tcp dport vmap @blacklist_tcp
    if "ens3" ip6 saddr . udp dport vmap @blacklist_udp
    dnat to tcp dport map @fwdtoip_tcp:tcp dport map @fwdtoport_tcp
    dnat to udp dport map @fwdtoip_udp:udp dport map @fwdtoport_udp
    ip6 daddr 2a01:729:16e:10::9998 redirect to :tcp dport map @redirect_tcp
    ip6 daddr 2a01:729:16e:10::9998 redirect to :udp dport map @redirect_udp
    ct status dnat accept
    }

Default behavior in ip6 filter forward table is to drop. This means that 
my above rules are blocked, I see (u18srv being the machine who will 
forward the traffic to another one):

18:32:00.476524 IP6 <hostname>.41174 > u18srv.12345: Flags [S], seq 
126955234, win 28640, options [mss 1432,sackOK,TS val 2255777795 ecr 
0,nop,wscale 7], length 0 
 

18:32:08.668468 IP6 <hostname>.41174 > u18srv.12345: Flags [S], seq 
126955234, win 28640, options [mss 1432,sackOK,TS val 2255785986 ecr 
0,nop,wscale 7], length 0
18:32:24.796392 IP6 <hostname>.41174 > u18srv.12345: Flags [S], seq 
126955234, win 28640, options [mss 1432,sackOK,TS val 2255802114 ecr 
0,nop,wscale 7], length 0

Now if I change my default value to accept for ip6 filter forward table, 
all is good.

Question: how can I add forward rule to filter table using the existing 
maps which are defined in nat tables ? Other solution ?

I thought that ct status dnat accept was the key to archieve my goal, 
seems not :(

Thanks for any hint

-- 
Daniel
TOOTAi Networks