> For clean Markdown of any page, append .md to the page URL. > For a complete documentation index, see https://docs.pixalate.com/llms.txt. > For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.pixalate.com/_mcp/server. # Blocking FAQ > Common questions about Pixalate's pre-bid block lists, including update frequency, delivery, thresholds, exceptions and how blocking relates to Analytics and the MRT. This page answers questions that apply to all of Pixalate's data feeds. Questions about one feed are answered on that feed's page; see [Questions about a specific feed](#questions-about-a-specific-feed). ## Feeds and updates #### What are the ways to block invalid traffic with Pixalate before the bid? * **Data feeds:** lists you load onto your own servers. See [Pre-bid data feeds](/data-feeds/overview) for every feed. * **Fraud API:** real-time lookups of one IP address, device ID or user agent at a time. See [Fraud API](/apis/fraud-api). * **Amazon DSP:** Pixalate filtering that you turn on in your line items. See [Amazon DSP](/data-feeds/amazon-dsp). * **Website tag blocking:** for publishers using Google Ad Manager. See [Website tag blocking](/data-feeds/website-tag-blocking). #### How often are the feeds updated? Feeds update at different frequencies: * **Hourly:** IPv4 IP block list, mobile device ID feed, CTV device ID feed. The CTV device ID feed has been hourly since August 28, 2026. * **Twice a day:** IPv6 IP block list. * **Weekly:** data center feeds (Fridays) and the malformed CTV bundle ID feed. * **Daily or weekly:** the user-agent feed, depending on the version you receive. Ask your account manager which version you're on. * **Daily:** all other feeds. See [How often each feed is updated](/data-feeds/overview#how-often-each-feed-is-updated) for the full table. #### How often should I check for new files? Match your checks to the feed's update frequency: * **Hourly feeds:** from the top of each hour, check every 15 minutes until the new file appears. * **Daily feeds:** check every hour, and keep checking after you download, since more than one file is occasionally uploaded in a day. * **Weekly feeds:** on Fridays, check every hour until the new file appears. Use each file's last-modified time, not its name, to tell whether it's new. See [Poll for new files](/data-feeds/delivery#poll-for-new-files). #### How are the feeds delivered? Every feed is a CSV file available over FTP. Some feeds can also be delivered through Amazon S3, AWS RTB Fabric or an API. See [Delivery methods](/data-feeds/delivery#delivery-methods). #### How big are the files? It depends on the feed. Device ID files can be up to 5 GB, and IP files up to 1 GB. See [Typical file sizes](/data-feeds/delivery#typical-file-sizes). #### Which High Risk Apps version should I use? Use version 2.0: [High Risk Mobile Apps 2.0](/data-feeds/high-risk-mobile-apps) and [High Risk CTV Apps 2.0](/data-feeds/high-risk-ctv-apps). High Risk Mobile App Lists 1.0 was deprecated on September 23, 2026. If you still receive a 1.0 list, contact your account manager to move to 2.0. ## Using the lists #### Can I choose not to block something that's on a list? Yes. The lists are pre-bid, and you apply them on your own servers, so you can apply them any way you want, including leaving out entries you don't want to block. #### What does the probability in a feed mean? Feeds such as the IP and device ID block lists give each entry a probability between 0.5 and 1. It's the likelihood that the entry is associated with the listed risk: 0.7 means 70%. The higher the number, the higher the risk. An entry needs a probability of at least 0.5 to be on the list. #### Where should I set my blocking threshold? Pixalate doesn't make a strong recommendation, because the right threshold depends on the quality and scale of your supply. Most clients start testing at 0.75 to 1 and adjust from there. As a general guide: | Probability | Meaning | | --------------- | ---------------------------------------- | | 1 | Only the worst offenders (deterministic) | | 0.90 or higher | Fraudulent beyond reasonable doubt | | 0.75 up to 0.90 | Clear and convincing evidence of fraud | | 0.5 up to 0.75 | More likely than not to be fraudulent | Lowering the threshold blocks more traffic, so check your impression delivery whenever you change it. #### How do I ask Pixalate to whitelist an IP address? 1. Tell Pixalate who the IP address belongs to, how it's used, whether bots are used in your testing, and when the problem started. Email [support@pixalate.com](mailto:support@pixalate.com) or contact your account manager. 2. Pixalate checks the IP's fraud type, and how many impressions come from it each day and how often. 3. If Pixalate confirms the IP is used for legitimate testing, it adds the IP to the whitelist. If not, the IP stays on the block list. #### Why is an app on a block list when its IVT looks low in my Analytics dashboard? Pixalate presents IVT differently in each place: * **Analytics** shows IVT in your own first-party data. * **The Media Ratings Terminal (MRT)** shows IVT based on Pixalate's global data, not only your traffic. * **The block lists** flag apps using Pixalate's own criteria. Not every IVT type measured in your Analytics data goes into the MRT, and not every IVT type flagged in your data leads to an app being added to a block list. IVT can come from compromised devices, bot farms or the app itself. Pixalate looks at how flagged impressions correlate with the app versus the devices generating them, so that an app isn't penalized for bad devices or misrepresented traffic. To find the source of problem devices, work directly with the seller or publisher. ## Questions about a specific feed | Topic | Answered on | | -------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------ | | How IPs are added, Tor and proxy IPs, IPv4 versus IPv6, missing last octets, X-Forwarded-For | [IP block lists (IPv4 and IPv6)](/data-feeds/ip-block-lists) | | The difference between the proxy gateway list and the IP block list | [Proxy gateway reference list](/data-feeds/proxy-gateway) | | Spoofed, malformed and do-not-track device IDs | [Mobile device ID feed](/data-feeds/mobile-device-ids) | | CTV device IDs, IFA types and device names | [CTV device ID feed](/data-feeds/ctv-device-ids) | | Matching on app ID, bundle ID and OS; why apps appear and drop off the list | [High Risk Mobile Apps 2.0](/data-feeds/high-risk-mobile-apps), [High Risk CTV Apps 2.0](/data-feeds/high-risk-ctv-apps) | | Delisted apps, the two DEFASE lists and how they differ from High Risk Apps | [Delisted apps (DEFASE)](/data-feeds/defase) | | Daily versus weekly user-agent files | [User-agent feed](/data-feeds/user-agents) | Still have a question? Contact your Pixalate account manager or [support@pixalate.com](mailto:support@pixalate.com).