DNSCrypt is an encrypted DNS tool released by OpenDNS. It encrypts DNS traffic and blocks common DNS attacks such as replay attacks, observation attacks, timing attacks, man-in-the-middle attacks, and resolver forgery attacks. DNSCrypt supports Mac OS and Windows, making it an excellent tool for preventing DNS pollution.
DNSCrypt uses an SSL-like encrypted connection to fetch resolutions from DNS servers, effectively countering DNS hijacking, DNS pollution, and man-in-the-middle attacks.
After running the Windows client version of DNSCrypt, it automatically displays the service status in the system tray and changes the DNS server address to 127.0.0.1, securely connecting to OpenDNS through local encryption. This way, all local DNS requests are encrypted to bypass DNS pollution and ultimately resolve to the correct IP addresses. Based on my testing, this tool can permanently solve all DNS pollution issues, including the recent DNS pollution targeting Dropbox.
DNSCrypt official introduction page: http://www.opendns.com/about/innovations/dnscrypt/
DNSCrypt download link: http://shared.opendns.com/dnscrypt/packages/windows-client/DNSCryptWin-v0.0.6.exe
DNSCrypt MAC version source code, Windows version source code.