In my situation I would like to connect to a wireless lan router which is secured with wpa2-psk. The router also uses dhcp.

The tools I have are ifconfig, iwconfig and dhcp. Is it possible to connect to my router with only this three tools? If so, how?

No.

You also need a supported wifi card, supporting libraries and wpa supplicant.
Here's a howto:
http://www.cyberciti.biz/tips/howto-...iguration.html

Out of curiosity, why didn't they just add WPA/WPA2 support into ifconfig and iwconfig? Those two works with open wifi networks and wep networks so why not wpa also? If nothing else, it's at least consistent and we won't have to figure out yet another tool just to handle wpa authentication.

If, hypothetically, in the future a new encryption protocol is devised due to exploitable weakness in wpa, will we have yet another different tool just to handle that protocol too instead of making everything streamline and well integrated?

IMO, this makes things harder to use rather than easier.

I am by no means an expert on this matter, but I do have some knowledge. I believe that the reasons for the need for wpa-supplicant is due to the complexities involved with the WPA and WPA2 authentications schemes, as the WPA2 has both WPA2-PSK and WPA2 enterprise which requires 802.11x authentication over Radius, which is probably why we need another application. Also when WPA came out before WPA2 there were many cards that didn't support anything but WEP due to older firmwares, and that wpa supplicant was needed to augment this shortcoming. Of course this is all conjecture on my part. Also don't forget this IS linux and they have about 30 different applications to do the same thing.