diff --git a/blockcheck.py b/blockcheck.py
index 95a3c41..70fe718 100755
--- a/blockcheck.py
+++ b/blockcheck.py
@@ -12,6 +12,7 @@ import os.path
 import dns.resolver
 import dns.exception
 import ipaddress
+import ipwhois
 
 '''
 
@@ -803,6 +804,18 @@ def check_ipv6_availability():
     print(": IPv6 недоступен.")
     return False
 
+def get_ispinfo(ipaddr):
+    try:
+        rdap_response = ipwhois.IPWhois(ipaddr)
+        ispinfo = rdap_response.lookup_rdap(depth=1)
+        return ispinfo['asn']
+    except (ipwhois.exceptions.ASNRegistryError,
+            ipwhois.exceptions.ASNLookupError,
+            ipwhois.exceptions.ASNParseError,
+            ipwhois.exceptions.HTTPLookupError,
+            ipwhois.exceptions.HTTPRateLimitError):
+        return False
+
 def main():
     ipv6_addr = None
     global ipv6_available
@@ -823,6 +836,12 @@ def main():
     if ip_isp:
         if ipv6_available:
             print("IP: {}, IPv6: {}, провайдер: {}".format(_mask_ip(ip_isp[0]), _mask_ip(ipv6_addr), ip_isp[1]))
+            if not force_ipv6:
+                asn4 = get_ispinfo(ip_isp[0])
+                asn6 = get_ispinfo(ipv6_addr)
+                if asn4 and asn6 and asn4 != asn6:
+                    ipv6_available = False
+                    print("Вероятно, у вас IPv6-туннель. Проверка IPv6 отключена.")
         else:
             print("IP: {}, провайдер: {}".format(_mask_ip(ip_isp[0]), ip_isp[1]))
         print()
diff --git a/requirements.txt b/requirements.txt
index 2f73596..655871c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1 +1,2 @@
 dnspython
+ipwhois