YaDirectFetcher
Yandex operates YaDirectFetcher, which downloads the target pages of ads to check their availability and topic before ad placement. Yandex states the robot does not use robots.txt and ignores directives set for it. Verify it by reverse DNS to a yandex.ru, yandex.net or yandex.com host with forward DNS confirmation, or the Yandex Webmaster IP check tool.
Mozilla/5.0 (compatible; YaDirectFetcher/1.0; Dyatel; +http://yandex.com/bots)What YaDirectFetcher does
The user-agent string is Mozilla/5.0 (compatible; YaDirectFetcher/1.0; Dyatel; +http://yandex.com/bots). Yandex says the robot downloads the target pages of ads to check that they are available and to check their topic, which Yandex describes as necessary for placing ads in search results and on partner sites. The pages it requests are the target pages of Yandex ads that point at your site, so a site that runs no Yandex ads has no stated reason to expect this robot's visits.
Allowing YaDirectFetcher is what lets Yandex confirm an ad's target page and place the ad. Blocking it at the server would stop those availability and topic checks, which per Yandex's description are required for ad placement. There is no robots.txt route, because Yandex states outright that the robot does not use the robots.txt file and ignores the directives set for it. A Disallow rule for the YaDirectFetcher token has no documented effect.
To verify a request, reverse-resolve the IP and confirm the host name ends in yandex.ru, yandex.net or yandex.com, then forward-resolve that host name and confirm it returns the same IP. Yandex Webmaster also has an IP address check tool. Yandex publishes no IP range file for this robot, so the DNS check and that tool are the only documented methods for separating YaDirectFetcher requests from traffic that merely carries its user-agent string.
Operator note. Yandex states explicitly: 'The robot doesn't use the robots.txt file and ignores the directives set for it.'
Controlling YaDirectFetcher with robots.txt
Use the token YaDirectFetcher in robots.txt. Yandex documents that this fetcher does not consult robots.txt, so a robots rule will not stop it; see the operator note.
User-agent: YaDirectFetcher
Disallow: /User-agent: YaDirectFetcher
Allow: /Verifying a request is really YaDirectFetcher
Anyone can put YaDirectFetcher in a User-Agent header. Reverse DNS lookup on the requesting IP must return a host ending in yandex.ru, yandex.net or yandex.com, and a forward DNS lookup of that host must return the same IP. Yandex Webmaster also provides an IP address check tool.
host <request-ip>
# expect a hostname ending in yandex.ru, yandex.net, yandex.com
host <that-hostname>
# expect it to resolve back to <request-ip>Common questions
Should I block YaDirectFetcher?
Yandex uses it to download ad target pages to check availability and topic, and says those checks are necessary for ad placement in search results and on partner sites. If you run Yandex ads pointing at your site, blocking the robot would interfere with that placement. Yandex documents no other effect of the visits.
Does YaDirectFetcher obey robots.txt?
No. Yandex's documentation states explicitly that the robot doesn't use the robots.txt file and ignores the directives set for it. A robots.txt rule for the YaDirectFetcher token has no documented effect, so any block would have to happen at the server level.
How do I verify YaDirectFetcher?
Reverse-resolve the requesting IP and check that the host name ends in yandex.ru, yandex.net or yandex.com, then forward-resolve that name and confirm it returns the same IP. Yandex Webmaster also provides an IP address check tool. Yandex publishes no IP range file for this robot.
Sources
Every fact on this page was checked against Yandex's own documentation, listed below, and re-checked by a second reviewer before publication. Reviewed September 2026.
Related crawlers
This registry documents how operators describe their own bots so site owners can identify and control them. It does not publish third-party IP lists or guess at undocumented behaviour. To see how your own site responds to automated visitors, the bot detection scanner reads a URL's live response and names the protection it finds.