Testing for signs of DNS hijacking
Router Checker is a free web-based tool you can use to check your device's connection to its DNS resolver, to make sure it is connecting to an authorized DNS server. A mismatch between the two may indicate DNS hijacking is underway.
Legacy Tool: DNSChecker
The old DNSCheck tool created in response to the 2011 DNSChanger botnet takedown remains available on the Labs Legacy Tools FTP server. The DNSCheck tool checks the PC's DNS settings for potentially malicious changes made by the DNSChanger malware. It can also be used to reset problematic DNS settings.
To use DNSChecker, download F-Secure_DNSCheck.zip from the Labs Legacy Tools FTP server.
Note: This is an F-Secure Labs support tool. It is provided 'as is' without warranty or product support.