[Nginx][Web] Client address and autodiscover adjustments

data/conf/nginx/templates/nginx.conf.j2

@@ -47,6 +47,13 @@ http {
         default "";
     }
 
+    # Client address for PHP: on the internal sogo-auth listener nginx itself is the client,
+    # the real address comes from the X-Real-IP header set by /sogo-auth-verify
+    map $sogo_auth_internal $mailcow_client_ip {
+        "1"     $http_x_real_ip;
+        default $remote_addr;
+    }
+
     {% if HTTP_REDIRECT %}
     # HTTP to HTTPS redirect
     server {

data/conf/nginx/templates/sites-default.conf.j2

@@ -116,7 +116,8 @@ location ~ \.php$ {
     include /etc/nginx/fastcgi_params;
     fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
     fastcgi_param PATH_INFO $fastcgi_path_info;
-    fastcgi_param HTTP_X_REAL_IP $remote_addr;
+    fastcgi_param REMOTE_ADDR $mailcow_client_ip;
+    fastcgi_param HTTP_X_REAL_IP $mailcow_client_ip;
     # trusted internal-auth marker; empty for external clients (see nginx.conf map)
     fastcgi_param SOGO_AUTH_INTERNAL $sogo_auth_internal;
     fastcgi_read_timeout 3600;