I'm using nginx to distribute the load over 3 webservers using the ip_hash method. When the listening socket is IPv4/IPv6 compatible ( listen [::]:443; ) only one of the backend servers are used. With the socket in IPv4 only mode ( listen 0.0.0.0:443; ) the module correctly distributes the load. It seems the hash isn't taking in account the size of the addresses and because the first 32bits oby pamribeirox - Nginx Mailing List - English