Does Safari 27 Block Bing UET and LinkedIn Tags?
In July, the Safari 27 beta write-ups agreed on a headline: Safari 27 blocks Bing UET and the LinkedIn Insight Tag by IP address, and first-party proxies will not save you. Safari 27 shipped on September 14, 2026. I found no one who had checked that claim against the stable release.
So I read the files. Safari’s tracker lists are downloaded into your user cache, not compiled into the browser. On October 9, 2026 I parsed the five that matter for marketing tags on my Mac (macOS 27.0.1, Safari 27.0.1) and checked the common martech hosts against them.
The short version: Bing UET and LinkedIn are on a list, but not the IP list. That list has five ranges, and none belongs to Microsoft or LinkedIn.
Dated note, October 9, 2026: this is a reading of the lists and of Apple’s and WebKit’s documentation, not a browser test, so it says "listed", not "blocked". Apple updates the lists silently. A live Web Inspector test on Safari 27.0.1 will be added here with its date.
Quick answer
Safari 27’s own tracker lists do not put Bing UET or the LinkedIn Insight Tag on its IP list. As read on October 9, 2026 from a Mac running Safari 27.0.1, that list holds five ranges (Google, Adobe and three Criteo) and nothing from Microsoft or LinkedIn. bat.bing.com and snap.licdn.com are on a different list, of known fingerprinting scripts, which Safari has applied in all browsing by default since Safari 26. That protection limits what the scripts can read, such as query strings and the referrer, and no block rule in these files names either host. Bing’s click ID msclkid is on the link-stripping list, which Apple documents for Private Browsing and for links opened from Mail and Messages.
Are these lists new in Safari 27?
No.
| File (what WebKit calls it) | Entries | Version stamp (inferred) | Current file created on this Mac |
|---|---|---|---|
FINGERPRINTING_SCRIPTS (fingerprinting scripts) | 217 hosts | January 8, 2026 | January 11, 2026 |
QUERY_PARAM (link filtering data) | 37 entries (29 everywhere, 8 limited to specific sites) | October 6, 2026 | October 8, 2026 |
TRACKING_SUBNETS (tracker network addresses) | 5 IP ranges | November 5, 2025 | November 21, 2025 |
TRACKING_DOMAINS (tracker domains) | 628 domains, each with an owner | November 5, 2025 | November 21, 2025 |
URL_FILTER (tracker block list) | 3,857 block rules across 180 domains | September 25, 2024 | May 2, 2025 |
A file can be replaced on update, so the last column is when the current copy was written, not when the list first existed. Even so, the fingerprinting list naming LinkedIn and Bing carries a January 2026 stamp and the IP list a November 2025 one. Safari 27 arrived on this Mac on September 18, 2026.
These are Apple’s current lists, not "Safari 27 lists". Neither Apple’s Safari 27 release notes nor WebKit’s Safari 27.0 post (September 17, 2026) has a privacy or tracking section.
Which Safari 27 tracking protection does each list feed, and when?
Each list feeds a different protection. For most of them, the mode is decided by one setting, Use advanced tracking and fingerprinting protection under Safari > Settings > Advanced, which covers Private Browsing by default or all browsing if the user chooses. The fingerprinting limits and the Mail and Messages link cleaning are the exceptions.
| List | Protection it feeds | Where Apple and WebKit document it by default |
|---|---|---|
| Fingerprinting scripts | Advanced Fingerprinting Protection: listed scripts get unreliable answers from fingerprintable APIs and cannot read query parameters or the referrer | All browsing, since Safari 26 |
| Link filtering | Link Tracking Protection: listed parameters are removed before a cross-site navigation | Private Browsing, plus links opened from Mail and Messages |
| Tracker block list | Blocking network loads of known trackers | Private Browsing (see the caveat below) |
| Tracker domains and IP ranges | Blocking cloaked first-party subdomains that point at a known tracker; WebKit’s cookie and cache code also consults the same lookup | Private Browsing |
- Fingerprinting. Apple’s June 2025 macOS 26 announcement says Safari "now offers advanced fingerprinting protection in all browsing by default." WebKit’s Safari 26.0 post lists the effects, including no reading of "query parameters and
document.referrer". WebKit’s current code adds the cookie and localStorage limit only with the advanced setting on. - Link Tracking Protection. Apple’s June 2023 announcement covers Messages, Mail and Private Browsing; WebKit’s Private Browsing 2.0 post (July 16, 2024) extends it to regular browsing when the advanced setting covers all browsing.
- Block list. The same post describes "an automatically enabled content blocker" in Private Browsing; the URL file is a list of third-party block rules.
- Tracker domains and IP ranges. WebKit’s code runs this check only with the advanced protections on and when a request goes to a different subdomain of the page’s own site, the first-party collection pattern WebKit calls "cloaked".
The caveat. WebKit’s current source also has a setting, on by default and not tied to Private Browsing, that loads the same block-rule list for every page. Its latest change landed on September 25, 2026, eleven days after Safari 27 shipped. Whether Safari 27.0.1 contains any version of it, I cannot tell from outside. Only a live test settles it.
Safari also hides IP addresses from known trackers by default (since Safari 15, per WebKit); Apple does not say which list defines them. And since its Safari 17 work, released from September 2023, it caps cookies from cloaked third-party IP addresses at seven days in all browsing, by heuristic, not list.
Does Safari 27 block Bing UET or the LinkedIn Insight Tag?
Not by IP, on the evidence of the lists.
| Check, October 9, 2026 | Bing UET | LinkedIn Insight Tag |
|---|---|---|
| Fingerprinting scripts | bat.bing.com listed | snap.licdn.com listed |
| IP ranges | No Microsoft range. bat.bing.com resolved to 150.171.27.10 and 150.171.28.10, outside all five | No LinkedIn range. px.ads.linkedin.com and snap.licdn.com resolved outside all five |
| Tracker domains | bat.bing.com, owner Microsoft | linkedin.com, not licdn.com |
| Block rules | None for bat.bing.com; the only Bing rule covers bing.com/actionp/ pings | None for snap.licdn.com or px.ads.linkedin.com; the only LinkedIn rule covers a share-count endpoint |
| Link-stripping list | msclkid listed | No LinkedIn parameter; li_fat_id, the click ID LinkedIn’s Conversions API documentation says to capture, is absent |
So the documented effect on both tags in regular browsing is the fingerprinting one: per Apple’s description, the script cannot reliably read the page’s query string or referrer, where a click ID and a traffic source live. Nothing in these files says the request itself is stopped, but I have not tested it, and the caveat above applies.
In Private Browsing, or with the advanced setting on all browsing, msclkid is on the list Safari’s documentation says it removes before the request, and the cloaked-subdomain check comes on. Neither is IP blocking of Microsoft’s servers.
What did the July beta write-ups get wrong?
TAGGRS, Stape and Hardal sell server-side tagging; PPC Land and Relevant Audience relay TAGGRS’s review. None has been updated for the stable release. Stape asks to be tested "once a stable release is out", the right instinct, and Hardal calls its Safari 27 points unconfirmed.
| Claim, as published | What the lists say on October 9, 2026 |
|---|---|
| "The Bing UET endpoint is blocked at both domain level and by IP subnet." TAGGRS, July 6 (updated July 30) | No Microsoft range and no block rule for bat.bing.com. It is listed as a fingerprinting script and a tracker domain |
| "Safari 27 blocks LinkedIn and Bing ad trackers by IP address." PPC Land headline, July 18 | Neither has an IP range. (PPC Land’s body puts LinkedIn on the fingerprinting list; only the headline says IP) |
| IP blocking is new in Safari 27 (TAGGRS, PPC Land) | The current IP file carries a November 2025 stamp. WebKit described blocking cloaked requests to known trackers in July 2024 |
| Tealium and "Blueonic" are on the fingerprinting list (TAGGRS, Stape, PPC Land) | Neither is. Both are on the block list, with 123 and 53 rules, which could explain Stape’s Private-mode Tealium result if the profile matches a rule |
| "First-party subdomains and server-side proxies do not evade the block." Relevant Audience, July 19 | A server-to-server call never passes through Safari. The IP check covers the browser’s own requests to a subdomain of your site |
| LinkedIn Insight and Segment are on the fingerprinting list | Correct |
| Threads, YouTube and X parameters were added to link stripping | They are on the list today (xmt, si, twclid, cn, cxt, t). Whether they were added in 27, I cannot see |
The write-ups found real list entries, then attached them to the wrong mechanism.
Which tags in a typical martech stack are on which list?
The table for a stack audit: listing only, as read on October 9, 2026. Many block rules target one script path, not the whole domain.
| Vendor | Fingerprinting scripts | Block rules | Tracker domains | IP range | Link parameters |
|---|---|---|---|---|---|
| Google (GTM, gtag, GA, Ads) | Legacy ssl.google-analytics.com and four ad and consent hosts | Yes: gtm.js, gtag/js, legacy GA, Ads conversion scripts | Yes | 216.239.32.0/19 | gclid, dclid |
| Adobe (Analytics, Launch, Audience Manager) | No | Yes: 216 for omtrdc.net, 133 for 2o7.net | Yes | 63.140.32.0/19 | s_cid |
| Microsoft (UET, Clarity) | bat.bing.com, www.clarity.ms | One ping rule | bat.bing.com | No | msclkid |
snap.licdn.com | One share-count rule | linkedin.com | No | No | |
| Meta pixel | No | Yes: fbevents.js, /tr/ | Yes | No | fbclid |
| HubSpot | js.hubspot.com, js.hs-analytics.net, EU host | Yes: analytics scripts | Yes | No | _hsenc and four more |
| Marketo Engage | No | Yes, including mktoresp.com/webevents/visitWebPage | Yes | No | mkt_tok |
| Salesforce | a.sfdcstatic.com, salesforceliveagent.com | Yes: Pardot pd.js | Yes | No | No |
| Mailchimp | No | No | Yes | No | mc_eid |
| Segment | cdn.segment.com | Yes: analytics.min.js | Yes | No | No |
| Tealium | No | Yes: 123 | Yes | No | No |
| Braze | js.appboycdn.com, Braze’s Web SDK host | No | No | No | No |
| Demandbase | tag.demandbase.com, scripts.demandbase.com | Three | Yes | No | No |
| 6sense | j.6sc.co | No | No | No | No |
| Criteo | static.criteo.net | Yes | Yes | Three ranges | No |
| TikTok | No | No | No TikTok host; five ByteDance-owned hosts | No | No ttclid |
Adobe is the row to read twice. Its first-party collection is a CNAME from your subdomain to Adobe, and the example target in Adobe’s setup documentation, hiodsibxvip01.data.adobedc.net, resolved inside the listed Adobe range from my machine, as did edge.adobedc.net. A first-party Adobe subdomain is the cloaked pattern the lookup would match. Google’s custom-domain target ghs.googlehosted.com resolved outside Google’s range; check from where your users are.
What happens to email click tracking?
mkt_tok (Marketo), mc_eid (Mailchimp) and five HubSpot parameters, including _hsenc, are on the link-stripping list. Whether a token is actually removed is a separate question, and I have not tested it.
Apple says Link Tracking Protection cleans links opened in Mail. But email platforms typically route the reader through a tracking redirect and add the token there. Then the token is not in the link Mail opens, and in a regular window, where link stripping is off by default, it may survive. A token in the link itself may be removed.
The stake is identity, not the click count: Adobe’s Marketo documentation says mkt_tok is used by "Marketo Landing Pages and Munchkin" to track a person, and that a link without it is still tracked. Mailchimp says mc_eid "identifies the recipient’s email address". Test with a real send (step Three) first.
When is server-side tagging the answer, and when is it not?
Server-side tagging moves the vendor call off the browser. Decide per tag, against the table.
It helps when a listed script is the one reading your identifiers. Your own first-party code can still read the landing URL, if the parameter arrives, and send the conversion server to server: Microsoft’s offline conversions, LinkedIn’s Conversions API, Google’s enhanced conversions. That is a capture problem; a server-side endpoint is one answer, and your CRM or back end can make the same call.
It helps when a vendor’s script or beacon is on the block list and your Private Browsing share matters. Check where your own endpoint resolves: a subdomain inside a listed range is the cloaked pattern.
It does not help with Link Tracking Protection. Where it applies, Safari removes the listed parameter before the navigation leaves the device, so no server sees it, yours included. For email, identify the person on a form or login, not from a URL token.
It does not help with tags on no list. That is buying infrastructure for a problem you do not have; measurement usually breaks earlier, as I wrote in why analytics implementations fail.
How to test it yourself in Safari 27’s Web Inspector
One. Read the lists on your own Mac.
cd "$(getconf DARWIN_USER_CACHE_DIR)com.apple.WebPrivacy"
ls -l
tail -c +73 FINGERPRINTING_SCRIPTS.wplist | grep -E 'bing|licdn|segment|hs-analytics'
tail -c +73 TRACKING_SUBNETS.wplist
tail -c +73 QUERY_PARAM.wplist
dig +short smetrics.example.com
Use your own collection subdomains in the last line and compare each address with the five ranges. Record the Safari version, window type and privacy settings with every result below.
Two. Open the developer tools in a Private window. In Safari > Settings > Advanced, select "Show features for web developers" and note the advanced-protection and "Hide IP address" settings. In a Private window, choose Develop > Show Web Inspector, open the Network tab and check Preserve Log.
Three. Test link stripping. From a page on a different site, click a link to your landing page carrying ?gclid=test1&msclkid=test2&mkt_tok=test3&utm_source=test4. If Link Tracking Protection applied, the document request shows utm_source and none of the other three. Repeat in a regular window. Then repeat with a real tracked link from a test send of your email platform, opened from Apple Mail in a regular window, and check whether the token arrives on the landing request.
Four. Test network blocking. In the Private window, then a regular one, load a page with your tags and filter the Network tab by vendor domain. A blocked load fails, and the Console logs a line beginning "Blocked connection to known tracker".
Five. Test the fingerprinting limits through the beacon. WebKit’s console logging for these limits is off by default, so a missing message proves nothing. Check whether your test click ID made it into the tag’s outgoing request, such as the call to bat.bing.com, and compare the same click in Chrome.
This is the Safari-specific part of the analytics implementation checklist’s "test on real Safari" line.
My working take
The mechanism is the whole decision. "Blocked by IP" means conversion data never leaves the browser and only a server-side path helps. "Listed as a fingerprinting script" means the tag may still fire but cannot read the click ID: a capture problem, with cheaper answers than a new hosting contract.
Three things in the lists matter more than the Bing and LinkedIn headline. Adobe and Google are the two analytics vendors with an IP range, and Adobe’s first-party CNAME is the textbook cloaked pattern. Email tokens from Marketo, HubSpot and Mailchimp are on the link-stripping list, and whether your sends lose them depends on how your platform builds links. And tags on no list, TikTok among them, need no Safari project at all.
What would change my take is the live test. If bat.bing.com fails to connect in a regular Safari 27 window with default settings, the lists are not the whole story, and I will say so here.
Frequently asked questions about Safari 27 tracking protection and marketing tags
Does Safari 27 block the Bing UET tag?
Not by IP address, on the lists Apple served to a Mac running Safari 27.0.1 on October 9, 2026: the IP list has no Microsoft range, and no block rule names bat.bing.com. The host is listed as a known fingerprinting script, which since Safari 26 limits what the script can read in all browsing, including the query string and referrer. msclkid is on the link-stripping list, which Apple documents for Private Browsing and links opened from Mail and Messages. No live test has been run yet.
Is the LinkedIn Insight Tag blocked in Safari 27?
It is listed, not shown to be blocked, as of October 9, 2026. snap.licdn.com is on Apple’s fingerprinting-scripts list, which restricts the script’s access to query parameters, the referrer and fingerprintable APIs. The lists hold no LinkedIn IP range and no block rule for the tag, and li_fat_id is not on the link-stripping list.
Which parameters does Safari 27’s Link Tracking Protection remove?
Apple’s list, read October 9, 2026, has 37 entries (34 distinct names), 29 applied everywhere and 8 only on specific sites. They include gclid, dclid, fbclid, msclkid, twclid, yclid, mkt_tok, mc_eid, _hsenc and four other HubSpot parameters, and s_cid. UTM parameters are not on it. Apple and WebKit document the protection for Messages, Mail and Private Browsing, and for regular browsing only when the user sets "Use advanced tracking and fingerprinting protection" to all browsing.
How I read the lists
The files sit in com.apple.WebPrivacy under the folder getconf DARWIN_USER_CACHE_DIR prints; Jeff Johnson of Lapcat Software documented it in June 2023, when the parameter file had 25 entries. On my Mac it held ten .wplist files, last rewritten October 8, 2026.
Each file is plain text after a 72-byte header. The first byte is a type number matching WebKit’s WebPrivacySPI.h (1 block list, 2 link filtering, 3 tracker domains, 4 tracker addresses, 9 fingerprinting scripts), which is how I mapped files to protections. Bytes 36 to 43 hold a millisecond timestamp I read as the version date. That is inferred: Apple does not document the format, but every value is a round minute, and for four files it precedes the current file’s creation by 1.6 to 16 days. Creation dates come from stat, DNS from this Mac’s resolver on October 9, and WebKit code from its main branch that day, which may differ from the 27.0.1 build. File hashes are in my working notes.
Sources I used
Verified at source: October 9, 2026.
- Apple: "Safari 27", released September 14, 2026
- Apple Developer release notes: Safari 27; Safari 26
- WebKit blog: Safari 27.0 features, September 17, 2026; Safari 26.0 features; "Private Browsing 2.0", July 16, 2024; Safari 17.0 features
- Apple Newsroom: macOS Tahoe 26, June 2025; iOS 26, June 2025; privacy features, June 2023
- Apple Safari User Guide for macOS 27: Advanced; Privacy; Develop menu; and WebKit’s Network tab reference
- WebKit source, main branch, read October 9, 2026: resource types; list loading; cloaking check; fingerprinting limits; console message; block list loaded per page
- Lapcat Software (Jeff Johnson): "Safari 17 Link Tracking Protection Details", June 2023
- Vendor documentation: Marketo
mkt_tok, updated October 7, 2026; Adobe first-party CNAME; Mailchimpmc_eid; LinkedIn Conversions API,li_fat_id - The July write-ups: TAGGRS, July 6, updated July 30, 2026; Stape, July 16; PPC Land, July 18; Relevant Audience, July 19; Hardal, July 20