Use the `is_ipv6()` function to determine if a string value represents a valid IPv6 address.
## Syntax
```sql
is_ipv6(<string>)
```
## Parameters
| Name | Type | Required | Description |
| :----: | :----: | :------: | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| string | string | Yes | The string field or literal value to evaluate for IPv6 validity. The IPv6 address can be either an explicit string using quotes (for example, "2606:4700:4700::1111") or a string field. |
## Returns
The `is_ipv6()` function returns a boolean value: true if the string is a valid IPv6 address, and false otherwise.
## Usage Notes
* The function expects a string input and will return NULL if the input field is NULL or not present.
* Validation is strictly for IPv6 address formats. The function will return false for standard IPv4 addresses (for example, "1.1.1.1").
* This function is typically used within the `alter` stage to tag records, or within the `filter` stage to isolate specific IPv6 network traffic.
## Examples
### Example 1: Filter the IPv6 Addresses
**Goal**: Filter a dataset to evaluate an `ip` field and return only the records containing a valid IPv6 address.
**XQL Code**:
```sql
dataset = ips_test_raw
| alter IsIpv6 = is_ipv6(ip)
| filter IsIpv6
```
**Explanation**: You use the `is_ipv6()` function in the `alter` stage to check the `ip` field and assign the boolean result to a new field named `IsIpv6`. Next, you apply the `filter` stage to return only the rows where `IsIpv6` evaluates to true. While the original dataset contained IPv4 addresses like "1.1.1.1" and "192.168.1.100" (which evaluate to false), the filtered output retains only the valid IPv6 addresses "FF0E::1" and "2606:4700:4700::1111".
**Output**:
| \_TIME | IP | \_VENDOR | \_PRODUCT | ISIPV6 |
| :--------------------: | :------------------: | :------: | :-------: | :----: |
| Mar 26th 2025 19:26:07 | FF0E::1 | ips | test | true |
| Mar 26th 2025 19:26:07 | 2606:4700:4700::1111 | ips | test | true |
## Related Articles
* **Stages**: [alter](../stages/alter), [filter](../stages/filter)
* **Functions**: [is\_ipv4()](is_ipv4), [is\_known\_private\_ipv4()](is_known_private_ipv4), [is\_known\_private\_ipv6()](is_known_private_ipv6), [incidr6()](incidr6)
* **Datasets**: [ips\_test\_raw](https://docs-cortex.paloaltonetworks.com/r/Cortex-XQL-Schema-Reference-Guide/Introduction)