Hi,
i have the same problem. any new solutions ?

Regards, Eric

My Setup is:

WORLD -> ( nginx ipv4 blancer ) -> ( 3 ipv4 webserver )
WORLD -> ( nginx ipv6 blancer ) -> ( 3 ipv6 webserver )

My Config is:
upstream lb4 {
server XXX.XXX.XXX.XXX:80;
server XXX.XXX.XXX.XXX:80;
server XXX.XXX.XXX.XXX:80;
}
upstream lb6 {
server [xxxx:xxxx:xxxx::xxxx]:80;
server [xxxx:xxxx:xxxx::xxxx]:80;
server [xxxx:xxxx:xxxx::xxxx]:80;
}
server {
listen 80; ## listen for ipv4
server_name lb.netsyn.eu;

access_log /var/log/nginx/xxx.xxx.eu.access.log;

location / {
proxy_pass http://lb4;
proxy_redirect off;
proxy_next_upstream error timeout invalid_header http_500;
proxy_connect_timeout 2;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}
}

server {
listen [::]:80 default ipv6only=on; ## listen for ipv6
server_name lb.netsyn.eu;

access_log /var/log/nginx/xxx.xxxx.eu.access.log;

location / {
proxy_pass http://lb6;
proxy_redirect off;
proxy_next_upstream error timeout invalid_header http_500;
proxy_connect_timeout 2;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}
}