diff --git a/respodns/dns.py b/respodns/dns.py
index a5b4a06..9b4d0c4 100644
--- a/respodns/dns.py
+++ b/respodns/dns.py
@@ -53,7 +53,7 @@ async def getaddrs(server, domain, opts):
 
 
 def process_result(res, ip, check, opts: Options):
-    from .ips import is_bogon, blocks
+    from .ips import is_bogon, is_block_target
     from .util import right_now
     from .structs import Entry
 
@@ -68,9 +68,7 @@ def process_result(res, ip, check, opts: Options):
     elif check.kind.startswith("bad"):
         reason = "okay" if "NXDOMAIN" in res else "redirect"
 
-    elif any(is_bogon(r) for r in res):
-        reason = "block"
-    elif any(blocked in res for blocked in blocks):
+    elif any(is_bogon(r) or is_block_target(r) for r in res):
         reason = "block"
 
     elif not any(len(r) > 0 and r[0].isdigit() for r in res):
diff --git a/respodns/ips.py b/respodns/ips.py
index 9c76855..a7773d6 100644
--- a/respodns/ips.py
+++ b/respodns/ips.py
@@ -82,11 +82,12 @@ blocks = {
     "217.175.53.72",
 }
 
-for i in range(1, 255):
-    blocks.add(f"156.154.112.{i}")
-    blocks.add(f"156.154.113.{i}")
-    blocks.add(f"156.154.175.{i}")
-    blocks.add(f"156.154.176.{i}")
+block_checks = [
+    "156.154.112.",
+    "156.154.113.",
+    "156.154.175.",
+    "156.154.176.",
+]
 
 gfw_ips = {
     "4.36.66.178",
@@ -372,3 +373,9 @@ bogon_checks = [
 
 def is_bogon(ip):
     return any(ip.startswith(check) for check in bogon_checks)
+
+
+def is_block_target(ip):
+    if ip in blocks:
+        return True
+    return any(ip.startswith(check) for check in block_checks)