What common sites are known to be troublesome for Tor use?

Question

Certain sites block traffic from known exit nodes, and some sites simply show a CAPTCHA due to excessive abuse, etc.

Is there a list of websites known to be troublesome for visitors using Tor?

Answer 1

This community wiki will list commonly used websites known to be troublesome for Tor users. These will be broken down into the following categories:

• Blocked
  • Access to Tor traffic completely blocked
• Limited by CAPTCHA
  • Access may require submitting a CAPTCHA or similar verification
• Otherwise Limited
  • Access is limited in some other way, e.g. certain functionality may be restricted or login may not be possible, but site can otherwise be functional

The purpose of this page is not to discuss fixes/workarounds.

If you have an update, make sure to follow the format that's been established, and the following guidelines:

1. Keep websites in alphabetical order under each heading.
2. Specify the date access to each website is confirmed to be blocked/hindered.
3. Include the reason for the block if provided by the provider.

Blocked entirely to Tor users

• HealthCare.gov: Since at least 4th December 2013
  • Returns "Unable to connect" in Tor Browser Bundle ¹

Limited by CAPTCHA

• CloudFlare

  • Websites served through CloudFlare have various levels of "challenge" required by IPs with a "threat level" over that set by the CloudFlare customer, usually a CAPTCHA ^{2 3}

• Google

  • Google websites will intermittently make visitors solve a CAPTCHA or tell them they have spyware installed. They may also slow down traffic from that IP address for a short time ⁴

Otherwise Limited

• 4chan: Since at least 11th December 2013

  • Tor users are banned from posting ⁵

• GitHub.com

• Vimeo

  • Reports "This video can’t be played with your current setup." in Tor Browser Bundle
  • Sometimes temporarily blocks an IP address ⁶

• Wikipedia: Since at least 8th January 2008

  • User unable to edit any article ⁷

• Mt.Gox: Warns users on signup: Attention: accessing your account via the Tor network and/or public proxies may result in a temporary suspension of your account, and having to submit documents for AML verification.⁸

• Bitcoin Forum: User unable to signup or post messages: Spam. (Auto-ban.) You may appeal here: banappeals-w6pquw43@theymos.e4ward.com . If you are using Tor, see https://bitcointalk.org/index.php?topic=99601.msg1089571#msg1089571

Answer 2

I've decided to test how well the top 50 websites work for Tor users, and to determine the pervasiveness of any blocking. I'm using a script that runs "torsocks midori -s http://foo.bar/" to snapshot sites. Midori is configured send a Firefox user agent string.

Results from the initial test series are here, and some exemplary histograms are here. I'll add additional text, highlighting the results, as I have time. I'll also update the image link as I include new data in the analysis.

Some websites (or services such as CloudFront) may serve rapidly loading CAPTCHA-challenge pages to Tor users. As Cammy_the_block has noted, this would skew my results, in that blocking in this way would increase apparent performance. However, I have not seen any CAPTCHA challenges in the snapshots that I've taken so far. If I do find a CAPTCHA-challenge snapshot for a given website, I can probably identify others based on size.