upstream sks_servers { server 192.168.0.55:11372 weight=10; server 192.168.0.61:11371 weight=10; } upstream sks_servers_primary { server 192.168.0.55:11372; } map $query_string $upstream_server { ~"op=stats" sks_servers_primary; default sks_servers; } ## location /pks { proxy_pass http://$upstream_server/pks; proxy_pass_header Server; add_header Via "1.1 keys2.kfwebs.net"; proxy_ignore_client_abort on; }