-            country_code = self._downloader.params.get('geo_bypass_country', None)
-            # If there is no explicit country for geo bypass specified and
-            # the extractor is known to be geo restricted let's fake IP
-            # as X-Forwarded-For right away.
-            if (not country_code and
-                    self._GEO_BYPASS and
-                    self._downloader.params.get('geo_bypass', True) and
-                    countries):
-                country_code = random.choice(countries)
-            if country_code:
-                self._x_forwarded_for_ip = GeoUtils.random_ipv4(country_code)
+
+            # Geo bypass mechanism is explicitly disabled by user
+            if not self._downloader.params.get('geo_bypass', True):
+                return
+
+            if not geo_bypass_context:
+                geo_bypass_context = {}
+
+            # Backward compatibility: previously _initialize_geo_bypass
+            # expected a list of countries, some 3rd party code may still use
+            # it this way
+            if isinstance(geo_bypass_context, (list, tuple)):
+                geo_bypass_context = {
+                    'countries': geo_bypass_context,
+                }
+
+            # The whole point of geo bypass mechanism is to fake IP
+            # as X-Forwarded-For HTTP header based on some IP block or
+            # country code.
+
+            # Path 1: bypassing based on IP block in CIDR notation
+
+            # Explicit IP block specified by user, use it right away
+            # regardless of whether extractor is geo bypassable or not
+            ip_block = self._downloader.params.get('geo_bypass_ip_block', None)
+
+            # Otherwise use random IP block from geo bypass context but only
+            # if extractor is known as geo bypassable
+            if not ip_block:
+                ip_blocks = geo_bypass_context.get('ip_blocks')
+                if self._GEO_BYPASS and ip_blocks:
+                    ip_block = random.choice(ip_blocks)
+
+            if ip_block:
+                self._x_forwarded_for_ip = GeoUtils.random_ipv4(ip_block)