---
title: "Test pages and your ad-serving domain"
description: "What your network's ad-serving domain controls, how to get your own domain (CNAME) set up through Epom support, and how to load a real tag on a hosted test page."
type: "howto"
audience: [admin]
keywords: [ad serving domain, host, own domain, CNAME, test pages, preview tag, network, multi-tenancy]
ui_path: "Admin → Audit & diagnostics → Test pages"
---

Fetch the complete documentation index at: https://epom.com/ad-server/docs/llms.txt. Use this file to discover all available pages before exploring further. Append .md to any documentation page URL to get its markdown version.

# Test pages and your ad-serving domain

An **ad-serving domain** is the hostname your ads are actually requested from. It is not
cosmetic: it is put into every invocation code, every impression beacon, every click redirect
and every conversion URL the platform generates, and it owns the cookies the ad server reads
back. Your ad tags are served from your network's ad-serving domain; to add a domain, change
the one your network or a set of sites and advertisers uses, or retire an old one, ask Epom
support or your account manager.

This page also covers the hosted **Test pages** you use to load a real tag on a real page —
for example after a domain change.

## Who this is for

Network administrators. The **Test pages** grid needs the *Test Pages* admin
permission (ask Epom support or your account manager to add it if your role lacks it) — see
[Users and roles](https://epom.com/ad-server/docs/guides/admin/users-and-roles.md).

## What a "network" means here

One installation is **one** network. There is no tenant switcher: branding and the default
domain apply installation-wide. Running several networks means running several
installations, each with its own data and its own domains — Epom support sets those up. See
[White-label & multi-tenancy](https://epom.com/ad-server/docs/concepts/white-label-and-multitenancy.md).

## Prerequisites

- For a test page: the invocation code you want to check, copied from the placement's
  **Ad Tags & API** card.

## Steps

### Maintain test pages

A test page is a small hosted HTML page you own, served anonymously at `/test/<id>.do`,
whose body is whatever markup you paste in. It is the standard way to load a real
invocation code on a real page, on the host it will really serve from.

1. Go to **Admin → Audit & diagnostics → Test pages**. The grid lists **ID**, **Title** and
   **Ad cache**, with **Add**, **Edit**, **Open** and **Delete** in the toolbar.
2. **Add** (or select a row and **Edit**) opens *Test page information*: **Title**
   (required, at most 64 characters), an **Add to ad cache** checkbox and a **Content** code
   editor. Paste your invocation code into Content and save; the toast reads *Done*.
3. Select the row and click **Open** to load `/test/<id>.do` in a new tab. The editor has
   the same **Open** button in its footer once the page has an ID.
   ![Test pages grid with three pages, one ticked, and the Add, Edit and Open buttons](https://epom.com/docs-images/ad-server/networks-and-domains/test-pages.webp)

## Use my own domain (CNAME) for ad tags, the control panel or files

Your account starts on Epom-provided hostnames. To serve from your own brand — say
`ads.northwind-media.com` for tags and `panel.northwind-media.com` for the control panel —
the new names have to exist in two places, and only the first one is yours to do:

1. **DNS (you).** In your domain's DNS, create a **CNAME** record for each subdomain, pointing
   to the Epom hostname Epom support gives you. Use separate subdomains for separate
   jobs (ad serving, control panel, creative files), so each can be moved on its own later.
2. **Registration (Epom).** Send the names to Epom support or your account manager. A hostname only becomes
   usable once it is registered for your network — until then it is not offered anywhere in
   the console, however correct the DNS is. Tell Epom support or your account manager which sites and advertisers
   (or the whole network) should move to the new name.
3. **Use it.** A registered ad-serving domain appears in the **Domain** picker on a
   placement's ad tag settings (with the *Set Ad-Serving Domain (Placement)* permission — see
   [Ad tags & API](https://epom.com/ad-server/docs/guides/inventory/ad-tags-and-api.md)); new tags are generated on the new name.

**Tags already on publishers' pages keep working** on the old hostname as long as it stays
registered and pointed at Epom — re-issuing codes is needed only for traffic you want on the
new name. Ask Epom support or your account manager to remove a domain only once nothing calls it any more.

> **Corner case — retargeting and cookie matching:** a browser lets a domain read only the
> cookies it set itself. If your retargeting pixel runs on one domain and the ad tag or VAST
> URL on another, the cookie the pixel set is never seen at ad time and cookie/DMP targeting
> matches nobody. Put the pixel and the tags that should match it on the **same** serving
> domain.

## Corner cases and gotchas

> **Warning:** moving to a new domain rewrites the hostname in every *newly generated* tag,
> but tags already deployed on publisher pages keep pointing at the old host. Keep the old
> domain serving until every publisher has re-deployed. The same applies to conversion pixels
> and Postback URLs already handed to partners; see
> [Get the pixel and S2S tracking code](https://epom.com/ad-server/docs/guides/conversions/s2s-and-pixels.md).

> **Corner case:** if the white-label **Redirect URL for ad-serving domain** is set, a
> console page requested on an ad-serving host is redirected to that URL. Hosted test pages
> are deliberately exempt, which is why a test page still loads on an ad-serving domain — the
> one way to exercise a tag on the host it will really serve from.

> **Corner case:** the **Add to ad cache** checkbox on a test page is not a CDN control,
> whatever the form's hint says. It makes the ad servers able to serve the page's content
> themselves. Leave it off for an ordinary tag-preview page.

## Per-role notes

- **Administrators** need **Test Pages** for the test-page grid. Epom support adds it to your
  role on request.

- **Publishers and advertisers** have no host controls. The host is applied silently to the
  tags they copy, and a domain change tells them nothing — pasted tags keep the old hostname.

## Related

- [Configure white-label branding](https://epom.com/ad-server/docs/guides/admin/white-label.md) — the redirect URL for console pages
  requested on an ad-serving host
- [White-label & multi-tenancy](https://epom.com/ad-server/docs/concepts/white-label-and-multitenancy.md)
- [Get the pixel and S2S tracking code](https://epom.com/ad-server/docs/guides/conversions/s2s-and-pixels.md) — the
  **Ad-serving domain** selector advertisers see, and what it governs
- [Ad tags & invocation API](https://epom.com/ad-server/docs/guides/inventory/ad-tags-and-api.md)
- [Review the actions log and troubleshooting log tasks](https://epom.com/ad-server/docs/guides/admin/system-ops.md) — the rest of
  *Audit & diagnostics*