YahooMailProxy
Email proxy crawler fetching URLs for security scanning
About this crawler
YahooMailProxy is a web crawler identified by the regular-expression pattern YahooMailProxy in the User-Agent request header. It is categorised as social-preview. Use the regex above to detect, log, allow, or block YahooMailProxy traffic in your web server, CDN edge rules, or robots.txt.
Block-rate · top 25k sites
No block-rate data for this crawler.
Technical details
- Name
- YahooMailProxy
- Pattern
YahooMailProxy- Tags
- social-preview
- Reference
- https://help.yahoo.com/kb/yahoo-mail-proxy-SLN28749.html
- Added
- 2026/04/17
- rDNS suffixes
.yahoo.co.jp,.yahoo.com,.yahoo.net- Instances
- 1 known sample(s)
rDNS verification (FCrDNS)
Verify a request is genuinely YahooMailProxy with forward-confirmed reverse DNS: the client IP's PTR record must end in one of the suffixes below and a forward A/AAAA lookup of that hostname must return the same IP. UA strings alone are spoofable; FCrDNS is not.
.yahoo.co.jp.yahoo.com.yahoo.net
Sample User-Agent strings
YahooMailProxy; https://help.yahoo.com/kb/yahoo-mail-proxy-SLN28749.html
Block this crawler
robots.txt — disallow YahooMailProxy:
User-agent: YahooMailProxy
Disallow: /
Apache .htaccess — return 403:
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} YahooMailProxy [NC]
RewriteRule .* - [F,L]
Nginx — return 403 inside a server block:
if ($http_user_agent ~* "YahooMailProxy") {
return 403;
}
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