This indicates an attack attempt to exploit a Policy Bypass vulnerability in D-Link DSL-2740R.
The vulnerability is due to insufficient sanitizing of user supplied inputs in the application when handling a crafted HTTP request. A remote attacker may be able to exploit this to change the system's DNS server setting, via a crafted request to the vulnerable service.
D-Link DSL-2740R all versions
System Compromise: Remote attackers can redirect traffic to malicious servers.
Apply the most recent upgrade or patch from the vendor.