---
title: "Cookie Detection Parameters"
slug: "cookie-detection-parameters"
updated: 2020-04-16T20:48:50Z
published: 2020-04-16T20:48:50Z
canonical: "onpremises.webtrends.help/cookie-detection-parameters"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://onpremises.webtrends.help/llms.txt
> Use this file to discover all available pages before exploring further.

# Cookie Detection Parameters

This set of parameters allows Webtrends Analytics to tie a visitor’s first hit with the rest of the visitor session. These parameters are generated and maintained by SmartSource Data Collector (SDC).

#### WT.co

`WT.co=Yes/No` SDC generates this parameter to determine whether the visitor’s browser supports and is configured to accept cookies. Valid values are `Yes` and `No`.

Example:

```
var coQueryParam = "&WT.co=" + navigator.cookieEnabled() ? "Yes" : "No";
```

#### WT.co_d

`WT.co_d=Cookie_Data` SDC generates this parameter the first time it attempts to set the cookie. The value is set to the value of the cookie. This parameter is generated only for “first visit” hits.

Webtrends Analytics and Visitor Data Mart use this parameter for “session stitching.” The first hit of the first visitor session (which may not have a cookie) gets the cookie value in the `WT.co_d` parameter. Subsequent hits that have the same value for the Webtrends cookie can be tied together with the `WT.co_d` hit to form a complete picture of the session. Also, SDC passes the `WT.co_d` value; it is not passed from the visitor’s web browser.

The Webtrends cookie format contains the IP address of the cookie’s connection address and the creation time. The creation time is represented as the number of seconds and nanoseconds since 1970 (standard UNIX time). A checksum is appended to the cookie value. The following example shows the format of the cookie value:

`WEBTRENDS_ID=IP Address-SSSSSSSSS.NNNNNN::checksum`

The following example shows the `WT.co_d` parameter with a Webtrends cookie value:

`WT.co_d=192.168.100.40-1045156016.29542554::A2D3FC34517CE562A9D4E33EF85D7B7F`

#### WT.co_a

`WT.co_a=Cookie_Data` SDC generates this parameter the first time it attempts to set the account cookie. Note that this parameter is generated only for hits on the first visit. This parameter is used to track visitor sessions across multiple accounts in Webtrends Analytics On Demand or multiple SmartSource data sources in Webtrends Analytics software.

This parameter is generated and the value is set to the account rollup cookie’s value if SDC attempted to set a first-time cookie for a given account. The global rollup cookie is named `ACOOKIE`. The global rollup cookie contains an encoded account rollup cookie named `WT_ACCT`. It contains the IP address of the cookie’s connection address and the creation time. The creation time is represented as the number of seconds and nanoseconds since 1970 (standard UNIX time). A checksum is appended to the cookie value. The following example shows the format of the cookie value:

`WT_ACCT=IP Address-SSSSSSSSS.NNNNNN::checksum`

The following example show the `WT.co_a` parameter with an account rollup cookie:

`WT.co_a=192.168.100.40-1045156016.29542554`

#### WT.co_f

`WT.co_f=uniqueIdentifier` SDC generates this parameter when you enable first-party cookie tracking in the Webtrends JavaScript tag. This parameter is passed on every hit so that Webtrends Analytics and Visitor Data Mart can use it for visitor session tracking.

`WT.co_f` uses the following format:

*IP Address-UniqueIdentifier:LastVisitTime.VisitStartTime* where the unique identifier is always 9-characters long and times use the epoch timestamp.

Example:

`WT.co_f= 192.168.100.40-123456789:1045156016.29542554`

You can configure the method that you want to use for your first party cookies in the SmartSource Data Source settings. For more information see "Tracking Visitor Sessions.”