diff --git a/apache2/apache2_util.c b/apache2/apache2_util.c
index f42436790..faef43f0c 100644
--- a/apache2/apache2_util.c
+++ b/apache2/apache2_util.c
@@ -284,12 +284,27 @@ static void internal_log_ex(request_rec *r, directory_config *dcfg, modsec_rec *
         }
         else hostname = "";
 
-#if AP_SERVER_MAJORVERSION_NUMBER > 1 && AP_SERVER_MINORVERSION_NUMBER > 2
+/* Non-standalone modules use amended format string for logging */
+#if !(defined(VERSION_STANDALONE))
+  #if AP_SERVER_MAJORVERSION_NUMBER > 1 && AP_SERVER_MINORVERSION_NUMBER > 2
 	ap_log_rerror(APLOG_MARK, APLOG_ERR | APLOG_NOERRNO, 0, r,
             "ModSecurity: %s%s [uri \"%s\"]%s", str1, hostname, log_escape(msr->mp, r->uri), unique_id);
-#else
+  #else
         ap_log_error(APLOG_MARK, APLOG_ERR | APLOG_NOERRNO, 0, r->server,
             "ModSecurity: %s%s [uri \"%s\"]%s", str1, hostname, log_escape(msr->mp, r->uri), unique_id);
+  #endif
+/* Standalone module must use original format string for logging with explicit
+ * "[client %s]" to log client IP address (no Apache to implicitly add this) */
+#else
+  #if AP_SERVER_MAJORVERSION_NUMBER > 1 && AP_SERVER_MINORVERSION_NUMBER > 2
+	ap_log_rerror(APLOG_MARK, APLOG_ERR | APLOG_NOERRNO, 0, r,
+            "[client %s] ModSecurity: %s%s [uri \"%s\"]%s", r->useragent_ip ? r->useragent_ip : r->connection->client_ip, str1,
+            hostname, log_escape(msr->mp, r->uri), unique_id);
+  #else
+        ap_log_error(APLOG_MARK, APLOG_ERR | APLOG_NOERRNO, 0, r->server,
+            "[client %s] ModSecurity: %s%s [uri \"%s\"]%s", msr->remote_addr ? msr->remote_addr : r->connection->remote_ip, str1,
+            hostname, log_escape(msr->mp, r->uri), unique_id);
+  #endif
 #endif
 
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