config: add ip rule pages.

en/docs/config/ip-rule.md

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+---
+hide:
+  - toc
+---
+
+# IP Rules
+
+smartdns provides IP address whitelist, blacklist and ignore rules for filtering results.
+
+| Parameter | Function | Usage |
+| --- | --- | --- |
+| whitelist-ip | Whitelist IP address | Accept IP addresses within a specified range |
+| blacklist-ip | Blacklist IP address | Accept IP addresses outside a specified range |
+| ignore-ip | Ignore IP address | Do not use a specific IP address, or range of IP addresses |
+| bogus-nxdomain | Spoof IP address filtering | Return SOA when the requested result contains a specified IP address |
+
+## Whitelist IP addresses
+
+If you want to restrict the IP addresses returned by an upstream server within a whitelist range, and disregard non-whitelisted addresses, you can set the following:
+
+```shell
+server -whitelist-ip
+whitelist-ip 192.168.1.1/24
+```
+
+## Blacklist IP addresses
+
+```shell
+server -blacklist-ip
+blacklist-ip 192.168.1.1/24
+```
+
+## Ignore IP addresses
+
+If you want to use a specific IP address returned by an upstream server, you can configure it to be ignored.
+
+```shell
+ignore-ip 1.2.3.4
+```
+
+## Spoof IP addresses
+
+If the ISP returns a 404 page containing a specific IP address range when the website does not exist, such as China Telecom's custom 404 page, you can use this parameter to return an SOA to the client instead of the ISP's redirect 404 page.
+
+```shell
+bogus-nxdomain 1.2.3.4
+```