Redirect a subdomain to a specific url using DNS
If you use an Apache server you can achieve this using .htaccess file. You can try adding following lines to the file and see whether it works.
RewriteEngine on
RewriteCond %{HTTP_HOST} ^(?:www\.)?subdomain.domain1\.com$
RewriteRule ^(.*)$ http://www.domain2.net/subfolder$1
(or)
RewriteEngine on
RewriteCond %{HTTP_HOST} ^subdomain\.domain1\.com$
RewriteRule ^(.*)$ www.domain2.net/subfolder$1
You can not do this with DNS. DNS is used to map domain names to IP address(es). It can not resolve a domain to a specific URI.