Merge pull request #562 from pi-hole/tweak/regex_reply

Add ;reply= regex extension documentation

docs/ftldns/configfile.md

@@ -42,11 +42,11 @@ Rate-limiting may be disabled altogether by setting `RATE_LIMIT=0/0` (this resul
 
 #### `REPLY_ADDR4` (no default, PR [#965](https://github.com/pi-hole/FTL/pull/965)) {#reply_addr4 data-toc-label='Force A reply'}
 
-When using `IP` blocking mode, `FTL` determines the address of the interface a query arrived on. We then use this IP address in the blocked reply. This setting can be used to overwrite the replied IPv4 (`A`) address.
+When using `IP` blocking mode, `FTL` determines the address of the interface a query arrived on. We then use this IP address in the blocked reply. This setting can be used to overwrite the replied IPv4 (`A`) address. It also overwrites the `A` record generated by the [`;reply=IP` regex extension](../regex/pi-hole.md#specify-reply-type)
 
 #### `REPLY_ADDR6` (no default, PR [#965](https://github.com/pi-hole/FTL/pull/965)) {#reply_addr6 data-toc-label='Force AAAA reply'}
 
-When using `IP` blocking mode, `FTL` determines the address of the interface a query arrived on. We then use this IP address in the blocked reply. This setting can be used to overwrite the replied IPv6 (`AAAA`) address.
+When using `IP` blocking mode, `FTL` determines the address of the interface a query arrived on. We then use this IP address in the blocked reply. This setting can be used to overwrite the replied IPv6 (`AAAA`) address. It also overwrites the `A` record generated by the [`;reply=IP` regex extension](../regex/pi-hole.md#specify-reply-type).
 
 #### `REPLY_WHEN_BUSY=DROP|ALLOW|BLOCK|REFUSE` (PR [#1156](https://github.com/pi-hole/FTL/pull/1156)) {#reply_when_busy data-toc-label='Database busy reply'}
 

docs/regex/pi-hole.md

@@ -56,6 +56,44 @@ will not block `abc` with type `AAAA` (but everything else) for the clients assi
 
 will block **not** block `abc` but **everything else**.
 
+## Specify reply type
+
+Pi-hole allows you to configure the reply it serves when a regular expression matches a query. This can be controlled via the `;reply` keyword.
+
+Valid options are:
+
+- `;reply=nodata` (an empty answer will be provided)
+- `;reply=nxdomain` ("no such domain" will be provided, can cause unintended side-effects)
+- `;reply=refused` (the query will be refused)
+- `;reply=none` (the query will be silently dropped)
+- `;reply=ip` (the Pi-hole's IP address if not overwritten by [`REPLY_ADDR4`](../ftldns/configfile.md#reply_addr4) and/or [`REPLY_ADDR6`](../ftldns/configfile.md#reply_addr6))
+- `;reply=1.2.3.4` (any valid IPv4 address)
+- `;reply=fe80::1234` (any valid IPv6 address)
+
+Only one option should be specified. An exception to this rule are the last two options which may be specified at the same time to configure both an IPv4 and an IPv6 address:
+
+- IPv4 only:
+
+  ``` plain
+  myregex;reply=1.2.3.4
+  ```
+
+  will result in `A 1.2.3.4` and `AAAA ::`
+- IPv6 only:
+
+  ``` plain
+  myregex;reply=fe80::1234
+  ```
+
+  will result in `A 0.0.0.0` and `AAAA fe80:1234`
+- IPv4 and IPv6:
+
+  ``` plain
+  myregex;reply=1.2.3.4;reply=fe80::1234
+  ```
+
+  will result in `A 1.2.3.4` and `AAAA fe80:1234`
+
 ## Comments
 
 You can specify comments withing your regex using the syntax