diff --git a/admin/pages.php b/admin/pages.php
index 56ad00e..8d1c49b 100644
--- a/admin/pages.php
+++ b/admin/pages.php
@@ -47,6 +47,12 @@ function dm_render_admin_page() {
                  '</p></div>';
         }
 
+        if ( isset( $_GET['checking'] ) && $_GET['checking'] && $current_tab === 'health' ) {
+            echo '<div class="notice notice-info"><p>' .
+                 __( 'Domain health check started. The check is running in the background.', 'wp-domain-mapping' ) .
+                 '</p></div>';
+        }
+
         if ( isset( $_GET['settings-updated'] ) && $_GET['settings-updated'] && $current_tab === 'health' ) {
             echo '<div class="notice notice-success is-dismissible"><p>' .
                  __( 'Settings saved.', 'wp-domain-mapping' ) .
@@ -74,7 +80,7 @@ function dm_render_admin_page() {
                  '</p></div>';
         }
         ?>
-
+    <div class="card domain-mapping-card">
         <!-- Tab Navigation -->
         <div class="domain-mapping-tabs">
             <?php foreach ( $tabs as $tab_key => $tab_label ) : ?>
@@ -104,7 +110,7 @@ function dm_render_admin_page() {
             </div>
         </div>
     </div>
-
+                </div>
     <script>
     function switchTab(tab) {
         // Update URL without reloading
@@ -549,18 +555,72 @@ function dm_render_health_content() {
 
     // Get health check results
     $health_results = get_site_option( 'dm_domain_health_results', array() );
+
+    // Check if batch processing is in progress
+    $health_check_progress = get_site_option( 'dm_health_check_progress', false );
     ?>
 
     <div class="card domain-mapping-card">
         <h2><?php _e( 'Domain Health Status', 'wp-domain-mapping' ); ?></h2>
 
-        <p>
-            <form method="post" action="">
-                <?php wp_nonce_field( 'dm_manual_health_check', 'dm_manual_health_check_nonce' ); ?>
-                <input type="hidden" name="dm_manual_health_check" value="1">
-                <input type="submit" class="button button-primary" value="<?php esc_attr_e( 'Check All Domains Now', 'wp-domain-mapping' ); ?>">
-            </form>
-        </p>
+        <?php if ( $health_check_progress !== false ) : ?>
+            <div class="notice notice-info">
+                <p>
+                    <?php _e( 'Health check in progress...', 'wp-domain-mapping' ); ?>
+                    <span id="health-check-progress-text">
+                        <?php
+                        printf(
+                            __( 'Processed %d of %d domains (%d%%)', 'wp-domain-mapping' ),
+                            $health_check_progress['processed'],
+                            $health_check_progress['total'],
+                            round( ( $health_check_progress['processed'] / $health_check_progress['total'] ) * 100 )
+                        );
+                        ?>
+                    </span>
+                </p>
+                <div class="progress-bar-outer" style="background-color: #f0f0f1; border-radius: 4px; height: 20px; width: 100%; overflow: hidden; margin-top: 10px;">
+                    <div id="health-check-progress-bar" class="progress-bar-inner" style="background-color: #2271b1; height: 100%; width: <?php echo round( ( $health_check_progress['processed'] / $health_check_progress['total'] ) * 100 ); ?>%; transition: width 0.5s;"></div>
+                </div>
+            </div>
+            <script>
+            jQuery(document).ready(function($) {
+                var healthCheckInterval = setInterval(function() {
+                    $.ajax({
+                        url: ajaxurl,
+                        type: 'POST',
+                        data: {
+                            action: 'dm_check_domain_health_batch',
+                            nonce: '<?php echo wp_create_nonce( 'dm_check_domain_health_batch' ); ?>'
+                        },
+                        success: function(response) {
+                            if (response.success) {
+                                if (response.data.complete) {
+                                    clearInterval(healthCheckInterval);
+                                    location.reload();
+                                } else {
+                                    $('#health-check-progress-text').text(
+                                        '<?php _e( 'Processed ', 'wp-domain-mapping' ); ?>' +
+                                        response.data.processed + ' <?php _e( 'of', 'wp-domain-mapping' ); ?> ' +
+                                        response.data.total + ' <?php _e( 'domains', 'wp-domain-mapping' ); ?> (' +
+                                        response.data.percentage + '%)'
+                                    );
+                                    $('#health-check-progress-bar').css('width', response.data.percentage + '%');
+                                }
+                            }
+                        }
+                    });
+                }, 2000);
+            });
+            </script>
+        <?php else : ?>
+            <p>
+                <form method="post" action="">
+                    <?php wp_nonce_field( 'dm_manual_health_check', 'dm_manual_health_check_nonce' ); ?>
+                    <input type="hidden" name="dm_manual_health_check" value="1">
+                    <input type="submit" class="button button-primary" value="<?php esc_attr_e( 'Check All Domains Now', 'wp-domain-mapping' ); ?>">
+                </form>
+            </p>
+        <?php endif; ?>
 
         <div class="tablenav top">
             <div class="tablenav-pages">
@@ -722,6 +782,14 @@ function dm_render_health_content() {
                         <p class="description"><?php _e( 'Send notifications when SSL certificates are expiring within this many days.', 'wp-domain-mapping' ); ?></p>
                     </td>
                 </tr>
+                <tr>
+                    <th scope="row"><label for="health_check_batch_size"><?php _e( 'Batch Size', 'wp-domain-mapping' ); ?></label></th>
+                    <td>
+                        <input name="health_check_batch_size" type="number" id="health_check_batch_size" min="5" max="50" class="small-text" value="<?php echo esc_attr( get_site_option( 'dm_health_check_batch_size', 10 ) ); ?>">
+                        <span><?php _e( 'domains per batch', 'wp-domain-mapping' ); ?></span>
+                        <p class="description"><?php _e( 'Number of domains to check in each batch. Lower values prevent timeouts but take longer.', 'wp-domain-mapping' ); ?></p>
+                    </td>
+                </tr>
             </table>
 
             <p class="submit">
diff --git a/assets/css/admin.css b/assets/css/admin.css
index cf62040..f61e5df 100644
--- a/assets/css/admin.css
+++ b/assets/css/admin.css
@@ -346,8 +346,13 @@
 
     .search-form-field {
         min-width: 100%;
+        width: auto;
     }
 
+    .regular-text {
+        max-width: 100%;
+        width: auto;
+    }
     .form-table th {
         width: 100%;
         display: block;
diff --git a/includes/class-tools.php b/includes/class-tools.php
index 449bed5..49b7106 100644
--- a/includes/class-tools.php
+++ b/includes/class-tools.php
@@ -73,14 +73,22 @@ class WP_Domain_Mapping_Tools {
             add_filter( 'manage_sites-network_columns', array( $this, 'add_site_id_column' ), 20 );
             add_action( 'manage_sites_custom_column', array( $this, 'display_site_id_column' ), 10, 2 );
             add_action( 'admin_print_styles', array( $this, 'site_id_column_style' ) );
+
+            // Add SSL and Reachable columns
+            add_filter( 'manage_sites-network_columns', array( $this, 'add_ssl_reachable_columns' ), 25 );
+            add_filter( 'wpmu_blogs_columns', array( $this, 'add_ssl_reachable_columns' ), 25 );
+            add_action( 'manage_blogs_custom_column', array( $this, 'display_ssl_reachable_column' ), 15, 3 );
+            add_action( 'manage_sites_custom_column', array( $this, 'display_ssl_reachable_column' ), 15, 3 );
         }
 
         // AJAX handlers
         add_action( 'wp_ajax_dm_check_domain_health', array( $this, 'ajax_check_domain_health' ) );
+        add_action( 'wp_ajax_dm_check_domain_health_batch', array( $this, 'ajax_check_domain_health_batch' ) );
         add_action( 'wp_ajax_dm_import_csv', array( $this, 'ajax_import_csv' ) );
 
         // Scheduled tasks
         add_action( 'dm_domain_health_check', array( $this, 'scheduled_health_check' ) );
+        add_action( 'dm_domain_health_check_batch', array( $this, 'process_health_check_batch' ) );
 
         // Admin init actions
         add_action( 'admin_init', array( $this, 'handle_export' ) );
@@ -152,6 +160,99 @@ class WP_Domain_Mapping_Tools {
         }
     }
 
+    /**
+     * Add SSL and Reachable columns
+     */
+    public function add_ssl_reachable_columns( $columns ) {
+        $new_columns = array();
+        $ssl_reachable_added = false;
+
+        foreach ( $columns as $key => $value ) {
+            // First add the current column
+            $new_columns[$key] = $value;
+
+            // Insert SSL and Reachable columns after the Site ID column
+            if ( $key === 'dm_site_id' && ! $ssl_reachable_added ) {
+                $new_columns['ssl_status'] = __( 'SSL', 'wp-domain-mapping' );
+                $new_columns['reachable_status'] = __( 'Reachable', 'wp-domain-mapping' );
+                $ssl_reachable_added = true;
+            }
+        }
+
+        // If Site ID column wasn't found but columns need to be added
+        if ( ! $ssl_reachable_added ) {
+            // Insert after checkbox (cb) column, before everything else
+            $final_columns = array();
+            foreach ( $new_columns as $key => $value ) {
+                $final_columns[$key] = $value;
+                if ( $key === 'cb' && ! $ssl_reachable_added ) {
+                    $final_columns['ssl_status'] = __( 'SSL', 'wp-domain-mapping' );
+                    $final_columns['reachable_status'] = __( 'Reachable', 'wp-domain-mapping' );
+                    $ssl_reachable_added = true;
+                }
+            }
+            return $final_columns;
+        }
+
+        return $new_columns;
+    }
+
+    /**
+     * Display SSL and Reachable column content
+     */
+    public function display_ssl_reachable_column( $column, $blog_id ) {
+        global $wpdb;
+
+        if ( $column == 'ssl_status' ) {
+            // Check if site uses HTTPS
+            $site_url = get_blog_option( $blog_id, 'siteurl', '' );
+            if ( strpos( $site_url, 'https://' ) === 0 ) {
+                echo '<span class="dashicons dashicons-lock" style="color: #46b450;" title="' . esc_attr__( 'SSL Enabled', 'wp-domain-mapping' ) . '"></span>';
+            } else {
+                echo '<span class="dashicons dashicons-unlock" style="color: #999;" title="' . esc_attr__( 'No SSL', 'wp-domain-mapping' ) . '"></span>';
+            }
+        }
+
+        if ( $column == 'reachable_status' ) {
+            // Check if this is the main site
+            if ( is_main_site( $blog_id ) ) {
+                // Main site is always reachable if we can access the admin
+                echo '<span class="dashicons dashicons-yes-alt" style="color: #46b450;" title="' . esc_attr__( 'Main site is accessible', 'wp-domain-mapping' ) . '"></span>';
+                return;
+            }
+
+            // Get primary domain for this blog
+            $domain = $wpdb->get_var( $wpdb->prepare(
+                "SELECT domain FROM {$this->tables['domains']} WHERE blog_id = %d AND active = 1 LIMIT 1",
+                $blog_id
+            ));
+
+            if ( ! $domain ) {
+                // No mapped domain, check original domain
+                $blog_details = get_blog_details( $blog_id );
+                if ( $blog_details ) {
+                    $domain = $blog_details->domain;
+                }
+            }
+
+            if ( $domain ) {
+                $health_result = dm_get_health_result( $domain );
+
+                if ( $health_result && isset( $health_result['accessible'] ) ) {
+                    if ( $health_result['accessible'] ) {
+                        echo '<span class="dashicons dashicons-yes-alt" style="color: #46b450;" title="' . esc_attr__( 'Site is accessible', 'wp-domain-mapping' ) . '"></span>';
+                    } else {
+                        echo '<span class="dashicons dashicons-warning" style="color: #dc3232;" title="' . esc_attr__( 'Site is not accessible', 'wp-domain-mapping' ) . '"></span>';
+                    }
+                } else {
+                    echo '<span class="dashicons dashicons-minus" style="color: #999;" title="' . esc_attr__( 'Not checked', 'wp-domain-mapping' ) . '"></span>';
+                }
+            } else {
+                echo '<span class="dashicons dashicons-minus" style="color: #999;" title="' . esc_attr__( 'No domain', 'wp-domain-mapping' ) . '"></span>';
+            }
+        }
+    }
+
     /**
      * Add custom styles for site ID column
      */
@@ -160,6 +261,8 @@ class WP_Domain_Mapping_Tools {
             ?>
             <style type="text/css">
                 th#dm_site_id { width: 3.5em; }
+                th#ssl_status { width: 3em; }
+                th#reachable_status { width: 5em; }
                 .dm-site-id-badge {
                     display: inline-block;
                     background: #2271b1;
@@ -195,6 +298,12 @@ class WP_Domain_Mapping_Tools {
         if ( $timestamp ) {
             wp_unschedule_event( $timestamp, 'dm_domain_health_check' );
         }
+
+        // Also clear any batch processing
+        $timestamp = wp_next_scheduled( 'dm_domain_health_check_batch' );
+        if ( $timestamp ) {
+            wp_unschedule_event( $timestamp, 'dm_domain_health_check_batch' );
+        }
     }
 
     /**
@@ -212,11 +321,11 @@ class WP_Domain_Mapping_Tools {
                 wp_die( __( 'You do not have sufficient permissions to perform this action.', 'wp-domain-mapping' ) );
             }
 
-            // Run the health check
-            $this->run_health_check_for_all_domains();
+            // Start batch processing
+            $this->start_health_check_batch();
 
             // Redirect back to health page
-            wp_redirect( add_query_arg( array( 'page' => 'domain-mapping', 'tab' => 'health', 'checked' => 1 ), network_admin_url( 'settings.php' ) ) );
+            wp_redirect( add_query_arg( array( 'page' => 'domain-mapping', 'tab' => 'health', 'checking' => 1 ), network_admin_url( 'settings.php' ) ) );
             exit;
         }
     }
@@ -241,11 +350,13 @@ class WP_Domain_Mapping_Tools {
             $health_notifications_enabled = isset( $_POST['health_notifications_enabled'] ) ? (bool) $_POST['health_notifications_enabled'] : false;
             $notification_email = isset( $_POST['notification_email'] ) ? sanitize_email( $_POST['notification_email'] ) : '';
             $ssl_expiry_threshold = isset( $_POST['ssl_expiry_threshold'] ) ? intval( $_POST['ssl_expiry_threshold'] ) : 14;
+            $batch_size = isset( $_POST['health_check_batch_size'] ) ? intval( $_POST['health_check_batch_size'] ) : 10;
 
             update_site_option( 'dm_health_check_enabled', $health_check_enabled );
             update_site_option( 'dm_health_notifications_enabled', $health_notifications_enabled );
             update_site_option( 'dm_notification_email', $notification_email );
             update_site_option( 'dm_ssl_expiry_threshold', $ssl_expiry_threshold );
+            update_site_option( 'dm_health_check_batch_size', max( 5, min( 50, $batch_size ) ) );
 
             // If auto check is enabled, ensure cron is set
             if ( $health_check_enabled ) {
@@ -280,6 +391,27 @@ class WP_Domain_Mapping_Tools {
             wp_send_json_error( __( 'No domain specified.', 'wp-domain-mapping' ) );
         }
 
+        // Check if this domain belongs to the main site
+        $main_site = get_site( get_main_site_id() );
+        if ( $main_site && $domain === $main_site->domain ) {
+            // Return success for main site without checking
+            $result = array(
+                'domain' => $domain,
+                'last_check' => current_time( 'mysql' ),
+                'dns_status' => 'success',
+                'dns_message' => __( 'Main site is always accessible', 'wp-domain-mapping' ),
+                'resolved_ip' => '',
+                'ssl_valid' => strpos( home_url(), 'https://' ) === 0,
+                'ssl_expiry' => '',
+                'accessible' => true,
+                'response_code' => 200
+            );
+
+            dm_save_health_result( $domain, $result );
+            wp_send_json_success( $result );
+            return;
+        }
+
         // Run health check
         $result = $this->check_domain_health( $domain );
 
@@ -290,6 +422,26 @@ class WP_Domain_Mapping_Tools {
         wp_send_json_success( $result );
     }
 
+    /**
+     * AJAX handler for batch domain health check
+     */
+    public function ajax_check_domain_health_batch() {
+        // Check permissions
+        if ( ! current_user_can( 'manage_network' ) ) {
+            wp_send_json_error( __( 'You do not have sufficient permissions to perform this action.', 'wp-domain-mapping' ) );
+        }
+
+        // Verify nonce
+        if ( ! isset( $_POST['nonce'] ) || ! wp_verify_nonce( $_POST['nonce'], 'dm_check_domain_health_batch' ) ) {
+            wp_send_json_error( __( 'Security check failed.', 'wp-domain-mapping' ) );
+        }
+
+        // Process next batch
+        $result = $this->process_health_check_batch( true );
+
+        wp_send_json_success( $result );
+    }
+
     /**
      * Scheduled health check
      */
@@ -299,38 +451,132 @@ class WP_Domain_Mapping_Tools {
             return;
         }
 
-        $this->run_health_check_for_all_domains();
+        $this->start_health_check_batch();
     }
 
     /**
-     * Run health check for all domains
+     * Start batch health check processing
      */
-    private function run_health_check_for_all_domains() {
+    private function start_health_check_batch() {
         global $wpdb;
 
         // Get all domains
         $domains = $wpdb->get_col( "SELECT domain FROM {$this->tables['domains']}" );
 
-        // Initialize issues array
-        $issues = array();
+        // Add original domains for sites without mapped domains (excluding main site)
+        $sites = get_sites( array( 'number' => 0 ) );
+        foreach ( $sites as $site ) {
+            // Skip main site
+            if ( is_main_site( $site->blog_id ) ) {
+                continue;
+            }
+
+            // Check if this site has a mapped domain
+            $has_mapped = $wpdb->get_var( $wpdb->prepare(
+                "SELECT COUNT(*) FROM {$this->tables['domains']} WHERE blog_id = %d",
+                $site->blog_id
+            ));
+
+            if ( ! $has_mapped ) {
+                $domains[] = $site->domain;
+            }
+        }
+
+        if ( empty( $domains ) ) {
+            return;
+        }
+
+        // Store domains in queue
+        update_site_option( 'dm_health_check_queue', $domains );
+        update_site_option( 'dm_health_check_progress', array(
+            'total' => count( $domains ),
+            'processed' => 0,
+            'started' => current_time( 'mysql' ),
+            'issues' => array()
+        ) );
+
+        // Schedule first batch
+        wp_schedule_single_event( time() + 1, 'dm_domain_health_check_batch' );
+    }
+
+    /**
+     * Process health check batch
+     *
+     * @param bool $return_data Whether to return data for AJAX
+     * @return array|void
+     */
+    public function process_health_check_batch( $return_data = false ) {
+        $queue = get_site_option( 'dm_health_check_queue', array() );
+        $progress = get_site_option( 'dm_health_check_progress', array() );
+
+        if ( empty( $queue ) ) {
+            // Batch processing complete
+            if ( ! empty( $progress['issues'] ) && get_site_option( 'dm_health_notifications_enabled', true ) ) {
+                $this->send_health_notification( $progress['issues'] );
+            }
+
+            // Clean up
+            delete_site_option( 'dm_health_check_queue' );
+            delete_site_option( 'dm_health_check_progress' );
+
+            if ( $return_data ) {
+                return array(
+                    'complete' => true,
+                    'message' => __( 'Health check completed.', 'wp-domain-mapping' )
+                );
+            }
+            return;
+        }
+
+        // Get batch size
+        $batch_size = get_site_option( 'dm_health_check_batch_size', 10 );
+
+        // Process batch
+        $batch = array_splice( $queue, 0, $batch_size );
+        $processed = 0;
+
+        // Get main site domain to skip it
+        $main_site = get_site( get_main_site_id() );
+        $main_domain = $main_site ? $main_site->domain : '';
+
+        foreach ( $batch as $domain ) {
+            // Skip main site domain
+            if ( $domain === $main_domain ) {
+                $processed++;
+                $progress['processed']++;
+                continue;
+            }
 
-        // Check each domain
-        foreach ( $domains as $domain ) {
             $result = $this->check_domain_health( $domain );
             dm_save_health_result( $domain, $result );
 
             // Check for issues
             if ( $this->has_health_issues( $result ) ) {
-                $issues[$domain] = $result;
+                $progress['issues'][$domain] = $result;
             }
+
+            $processed++;
+            $progress['processed']++;
         }
 
-        // Send notifications if enabled and issues exist
-        if ( ! empty( $issues ) && get_site_option( 'dm_health_notifications_enabled', true ) ) {
-            $this->send_health_notification( $issues );
+        // Update queue and progress
+        update_site_option( 'dm_health_check_queue', $queue );
+        update_site_option( 'dm_health_check_progress', $progress );
+
+        // Schedule next batch if needed
+        if ( ! empty( $queue ) && ! $return_data ) {
+            wp_schedule_single_event( time() + 2, 'dm_domain_health_check_batch' );
         }
 
-        return true;
+        if ( $return_data ) {
+            return array(
+                'complete' => empty( $queue ),
+                'total' => $progress['total'],
+                'processed' => $progress['processed'],
+                'remaining' => count( $queue ),
+                'percentage' => round( ( $progress['processed'] / $progress['total'] ) * 100 )
+            );
+        }
     }
 
     /**
@@ -675,6 +921,9 @@ class WP_Domain_Mapping_Tools {
         $errors = 0;
         $log = array();
 
+        // Track processed domains to prevent duplicates
+        $processed_domains = array();
+
         // Skip header row
         if ( $has_header ) {
             fgetcsv( $file );
@@ -700,6 +949,20 @@ class WP_Domain_Mapping_Tools {
             $domain = dm_clean_domain( trim( $data[1] ) );
             $active = intval( $data[2] );
 
+            // Check if we've already processed this domain
+            if ( isset( $processed_domains[$domain] ) ) {
+                $log[] = array(
+                    'status' => 'warning',
+                    'message' => sprintf( __( 'Row %d: Domain %s already processed in this import. Skipped duplicate.', 'wp-domain-mapping' ), $row_num, $domain )
+                );
+                $skipped++;
+                $row_num++;
+                continue;
+            }
+
+            // Mark domain as processed
+            $processed_domains[$domain] = true;
+
             // Validate blog_id
             if ( $blog_id <= 0 ) {
                 $log[] = array(
diff --git a/wp-domain-mapping.php b/wp-domain-mapping.php
index 08f3603..82a777c 100644
--- a/wp-domain-mapping.php
+++ b/wp-domain-mapping.php
@@ -3,7 +3,7 @@
  * Plugin Name: WP Domain Mapping
  * Plugin URI: https://wenpai.org/plugins/wp-domain-mapping/
  * Description: Map any site on a WordPress website to another domain with enhanced management features.
- * Version: 2.0.0
+ * Version: 2.0.2
  * Author: WPDomain.com
  * Author URI: https://wpdomain.com/
  * Network: true
@@ -20,7 +20,7 @@ if ( ! defined( 'ABSPATH' ) ) {
 }
 
 // Define plugin constants
-define( 'WP_DOMAIN_MAPPING_VERSION', '2.0.0' );
+define( 'WP_DOMAIN_MAPPING_VERSION', '2.0.2' );
 define( 'WP_DOMAIN_MAPPING_DIR_URL', plugin_dir_url( __FILE__ ) );
 define( 'WP_DOMAIN_MAPPING_DIR_PATH', plugin_dir_path( __FILE__ ) );
 define( 'WP_DOMAIN_MAPPING_BASENAME', plugin_basename( __FILE__ ) );