diff --git a/lib/core/settings.py b/lib/core/settings.py
index 409e5d11f..fb91c66fb 100644
--- a/lib/core/settings.py
+++ b/lib/core/settings.py
@@ -66,6 +66,9 @@ CONCAT_VALUE_DELIMITER   = '|'
 # coefficient used for a time-based query delay checking (must be >= 7)
 TIME_STDEV_COEFF = 10
 
+# standard deviation after which a warning message should be displayed about connection lags
+WARN_TIME_STDEV = 0.5
+
 # minimum length of usable union injected response (quick defense against substr fields)
 UNION_MIN_RESPONSE_CHARS = 10
 
diff --git a/lib/request/connect.py b/lib/request/connect.py
index 0236386b3..664be1212 100644
--- a/lib/request/connect.py
+++ b/lib/request/connect.py
@@ -46,6 +46,7 @@ from lib.core.exception import sqlmapSyntaxException
 from lib.core.settings import HTTP_SILENT_TIMEOUT
 from lib.core.settings import META_REFRESH_REGEX
 from lib.core.settings import MIN_TIME_RESPONSES
+from lib.core.settings import WARN_TIME_STDEV
 from lib.core.settings import URI_HTTP_HEADER
 from lib.core.threads import getCurrentThreadData
 from lib.request.basic import decodePage
@@ -501,6 +502,12 @@ class Connect:
                 while len(kb.responseTimes) < MIN_TIME_RESPONSES:
                     Connect.queryPage(content=True)
 
+                if stdev(kb.responseTimes) > WARN_TIME_STDEV:
+                    warnMsg  = "there are considerable lags in connection "
+                    warnMsg += "response(s). please use as high value for "
+                    warnMsg += "--time-sec option as possible (e.g. 10)"
+                    logger.critical(warnMsg)
+
         if conf.safUrl and conf.saFreq > 0:
             kb.queryCounter += 1
             if kb.queryCounter % conf.saFreq == 0: