Update 'what-to-do.md'

what-to-do.md

@@ -140,14 +140,45 @@ deny 2c0f:f248::/32;
 }
 ```
 
-> Method B: Show warning message
+> Method B: Redirect to warning page
 
 ```
-writing now
+http {
+...
+geo $iscf {
+default 0;
+173.245.48.0/20 1;
+103.21.244.0/22 1;
+103.22.200.0/22 1;
+103.31.4.0/22 1;
+141.101.64.0/18 1;
+108.162.192.0/18 1;
+190.93.240.0/20 1;
+188.114.96.0/20 1;
+197.234.240.0/22 1;
+198.41.128.0/17 1;
+162.158.0.0/15 1;
+104.16.0.0/12 1;
+172.64.0.0/13 1;
+131.0.72.0/22 1;
+2400:cb00::/32 1;
+2606:4700::/32 1;
+2803:f800::/32 1;
+2405:b500::/32 1;
+2405:8100::/32 1;
+2a06:98c0::/29 1;
+2c0f:f248::/32 1;
+}
+...
+}
+
+server {
+...
+if ($iscf) {rewrite ^ https://example.com/cloudflare.html;}
+...
+}
 ```
 
-
-
 - Set up [Tor Onion Service](https://www.torproject.org/docs/onion-services.html.en) or I2P insite if you believe in freedom and welcome anonymous users.
 
 - Ask for advice from other [Clearnet/Tor dual website operators](https://trac.torproject.org/projects/tor/wiki/org/projects/WeSupportTor) and make anonymous friends! :)