add validator list threshold

docs/infrastructure/configuration/configure-validator-list-threshold.md

@@ -0,0 +1,40 @@
+---
+seo:
+    description: Set the minimum number of UNL publisher lists a validator must be on for your server to use it.
+labels:
+  - Core Server
+  - Blockchain
+---
+# Configure Validator List Threshold
+
+A `rippled` server uses validators that meet a minimum intersection threshold between UNL publishers. This means a server only uses validators that exist on a number of validator lists, as defined by the server owner. {% badge href="https://github.com/XRPLF/rippled/releases/tag/2.4.0" %}New in: rippled 2.4.0{% /badge %}
+
+By default, the minimum threshold is calculated as follows:
+
+- floor(`validator_list_keys` / 2) + 1
+- If there are only 1 or 2 `validator_list_keys`, the threshold is `1`.
+
+
+## Modify the Validators File
+
+1. Edit the `validators.txt` file. The recommended installation places this file at:
+    ```
+    /etc/opt/ripple/validators.txt
+    ```
+
+2. Add the following stanza and a valid threshold number.
+
+    ```
+    [validator_list_threshold]
+    0
+    ```
+
+Be sure to save the changes and restart your server.
+
+{% admonition type="info" name="Note" %}If this value is `0` or isn't set, the threshold will be calculated using the default method. The value also can't be larger than the number of `validator_list_keys`.{% /admonition %}
+
+## See Also
+
+- [validators method][]
+
+{% raw-partial file="/docs/_snippets/common-links.md" /%}