I have never been able to connect to Steam with my D-Link DI-524 router. This is a wireless router, but I am using a hard-wired connection. I even replaced the router with a hardware version A3 and updated to the latest firmware.
Steam - Error
Could not connect to Steam network.
This could be due to a problem with your Internet connection, or with the Steam network. Please visit www.steampowered.com for more info.