List of services blocking Tor

List Of Services Blocking Tor

The Tor community maintains the following three lists (RBL blocks, Blocking software, and Individual blocks) as part of the DontBlockMe project. It is the opposite of the WeSupportTor project.

Glossary

CDN - A Content Delivery Network: these are networks that websites use to serve high amounts of traffic to their clients. CDNs can be geographically distributed to provide "local" copies of web content to people worldwide.
Exit relay - This is a Tor relay that exits traffic onto the plain Internet. All Tor traffic (though not when using onion services) appears to originate from these exit relays.
Non-exit relay - A Tor relay that does not act as an exit relay. A non-exit relay does not originate any traffic other than to other Tor relays and thus there is no necessary reason for services to block traffic from them. Guard and middle relays are the two types of non-exit relays, and many non-exit relays act as both types at the same time.
TCP RST - The TCP reset (or reject) is a way to gracefully close connections. Many services/software to block Tor traffic may block by explicitly closing the connection instead of ignoring the traffic.
TCP timeout - A TCP timeout is another way to block Tor traffic on the protocol- or routing-level, however it involves silently ignoring the traffic instead of rejecting it.

List of RBL Blocking Services

An RBL is a "realtime blackhole list" which is a DNS query-based list used to tag IP addresses as being malicious or as being an origin of spam. Due to the inability to filter or monitor Tor user behavior across the entire network, many Tor exit relay IPs will be marked as threatening (even indiscriminately) which means many legitimate web surfers will be incidentally included in such blocks. This is a subproject to routinely search for and clear Tor relay nodes from RBL and RBL-like lists.

Format:

[URL] - Description of service/list, threat detection and consequences for Tor users
[https://www.abuseat.org/] - Composite Blocking List (CBL) - A Division of SPAMHAUS. By policy, TOR nodes cannot be removed from the CBL list. - Thus, the exact reason for being listed can no longer be established by the individual Tor .Exit Relay operator. Consequently, trying to effectively handle any 'abuse' issues being unfortunately perpetrated from an individual Tor .Exit Relay has become increasingly difficult or impossible when referencing this resource.
[https://akismet.com/] - Blog comment spam protection. (Note: Previously this entry was "askimet.com", a misspelled version of "akismet" that redirected to the official site. It is not known whether this was a typo or a malicious website. Edited 10/5/2016)
[https://www.blocked.com/] - Web request blocker against proxies and anonymity networks. The site itself is not available over Tor.
[https://blogspam.net/] - Blog and forum content spam protection.
[https://www.cloudflare.com/] - Announces itself as Cloudflare. Blog post on Tor: https://blog.cloudflare.com/the-trouble-with-tor/.
[https://www.dan.me.uk/dnsbl] - Blocklist designed to identify all Tor relays, even ones that do not exit traffic. There are both a list for exit relays as well as for all relays, though the provider does warn against using the list of all relays. The site itself is not available over Tor.
[https://www.incapsula.com/] - Announces itself as Incapsula. Blog post on Tor.
https://www.imperva.com/ - Announces itself as Personalized Security
[https://www.imunify360.com/] - Announces itself as "Imperva Cloud Application Security"
[https://www.norse-corp.com/] - Web and networking protection including IP blocking.
[https://www.projecthoneypot.org/] - Honeypot for e-mail harvesters by listing unique e-mail addresses on web pages.
[https://recaptcha.net/] - the CAPTCHAs given are, on occasion, very difficult and timed [last check: 2015-11-21]
[https://stopforumspam.com/] - IP-based blocking service based on forum and blog spam. The site itself is available from some Tor Exits, but not others (403 Forbidden). [last check: 2015-09-15, 1/10 Exits Blocked]
[https://en.wikipedia.org/wiki/Webroot] - Webroot, specifically their service BrightCloud(R) "Threat Intelligence" (brightcloud.com), provides block lists to customers that includes Tor middle nodes marked as "Proxy." [Last checked 2018-04-17]

List Of Software Used To Block Tor

A listing of the software that has been identified as being used by the services listed below. This can present via another avenue to accomplish the goals of the DontBlockMe project. The format is:

[URL] - How to identify the blocking software when used by a service
[https://akamai.com/] Fifa.com, tdbank.com, expedia.com, www.ecb.europa.eu, discussions.apple.com seem to be using Akamai and use some sort of configuration that blocks Tor (not all Akamai sites block Tor). Akamai blocks usually present with a basic page saying "Access Denied" and a 'reference' note like "Reference !#18..." You can definitively confirm whether a site uses the Akamai CDN by running a WHOIS on the site's domain and looking for akam.net nameservers. Akamai report on Tor traffic.
[http://www.bluehost.com/] - Web hosting company. Block page has the phrase "If you feel this is in error please contact your hosting provider's abuse department".
[https://www.incapsula.com/] - Announces itself as Incapsula. Blog post on Tor: https://www.incapsula.com/blog/tor-does-not-equal-deny-access.html.
Convio/Blackbaud - A web host for various nonprofits. Blocks Tor specifically, returning an HTTP 501 error: "Not Implemented Tor IP not allowed". A traceroute leads to a subdomain of convio.net. http://www.adl.org/ is one affected site [last check: 2015-07-15].
Distil Networks - Anti-scraping company. Serves a captcha or block page with a form to request unblocking. Sample block pages: https://www.distilnetworks.com/distil_r_captcha.html, https://www.distilnetworks.com/distil_r_blocked.html #Distil #Distil https://www.distil.it/. Blog post on Tor: https://resources.distilnetworks.com/h/i/246101200-cloudflare-vs-tor-is-ip-blocking-causing-more-harm-than-good/181642.

How to unblock Tor users

See: Best Practices. If you run a web site on Cloudflare, and you don't want Tor users to see captchas, then whitelist the "T1" country code in the Access Rules of the Cloudflare Firewall app. See this article for more information. The best option is not using Cloudflare at all. There are many alternative self-hosting options. See The Great Cloudwall for more information.

Ad-hoc Solutions for accessing blocked content on Tor

There are various ad-hoc ways by which Tor Browser users may access websites that block Tor. All of these solutions involve fetching content via other websites, a privacy tradeoff.

= Service =	URL	Comment	Allows embedded non-static content?	Allows PDF/.exe/mp3?
The Internet Archive's WaybackMachine	`web.archive.org/save/_embed/<URL>`	Archive.org respects robots.txt restrictions, works best with JS enabled	No	Yes
Archive.fo	`archive.fo/?run=1&url=<URL>` And their official onion service: `archivecaslytosk.onion/?run=1&url=<URL>`	Ideal for news sites, doesn't require JS	No	No
Google Cache	`webcache.googleusercontent.com/search?q=cache:<URL without "http://">`	Google sometimes blocks these requests	No - static only	No
Startpage.com	(1) Find the URL by searching, (2) Click on the `proxy` option	Not always efficacious	No	No
Searx.me	(1) Find the URL by searching, (2) Click on the `proxied` option	Not always efficacious	No	No
Hypothes.is	`via.hypothes.is/<URL>`	Behind Cloudflare	Yes	Yes
Online Proxies	`hide.me/en/proxy`		Yes	Yes
	`www.proxysite.com/`		Yes	Yes
	`www.proxysite.club/`		Yes	Yes
	`hidester.com/proxy`	JS disabled by default	Yes	Yes
	`youtubeunblocks.com/`	JS disabled by default	Yes	Yes

Other relevant services

To avoid captchas that are often required when visiting YouTube, use this. To avoid captchas that are often required when visiting YouTube, use hooktube.com/ (behind Cloudflare recaptchas).
imgur.com blocks Tor uploads, to upload images on an imgur domain go to a stackexchange website (for example tor.stackexchange.com), click on Ask a Question, use the image upload tooltip to upload the image, the resulting url will have a i.stack.imgur.com/... form.
If you want to know which site is harassing Tor users or behind CloudFlare, try using this search engine.

Field guide to common block pages

Akamai

Access Denied
You don't have permission to access "%websitename%" on this server.
Reference #[\d\.a-f]+

Akamai is a CDN.

Bad Behavior

Bad Behavior is an antispam PHP plugin.

Blackbaud

Not implemented  Tor IP not allowed.

Blackbaud does web hosting for nonprofits.

Bluehost

Bluehost is a web hosting company. This seems to be their source code that is the source of the message: mod_rbld.

Cloudflare

Backward compatibility anchor for the old "CloudFlare" name.

[=#CloudFlare]

One more step
Please complete the security check to access %websitename%

Cloudflare is a CDN acting as MITM by design, decrypting all TLS (HTTPS) traffic to plaintext and harming users privacy by (feature called flexible SSL) intransparently forwarding traffic from https end-user in plaintext to origin webserver most of time. See The Great Cloudwall.

Distil

Access To Website Blocked

Distil Networks is an anti-bot/anti-scraping company. They also have challenge pages that are less severe than this block page (which has status code 456).

imperva

[=#Imperva]

%websitename% - Additional security check is required
Why am I seeing this page?
The website you are visiting is protected and accelerated by Incapsula. Your computer may have been infected by malware and therefore flagged by the Incapsula network. Incapsula displays this page for you to verify that an actual human is the source of the traffic to this site, and not malicious software.

What should I do?
Just click the I'm not a robot checkbox to pass the security check. Incapsula will remember you and will not show this page again. We recommend you run a virus and malware scan on your computer to remove any infection. 

Powered by imperva

imperva

Imunify360

[=#Imunify360]

%websitename%
is protected by Imunify360
We have noticed an unusual activity from your IP %exitIP% and blocked access to this website.

Imunify360