Where do I configure DNS and IP settings in HTC Desire S?

HTC Desire S seems to have very scarce WiFi settings. I'm trying to debug a Wifi connectivity issue and looks like it might be a DNS problem . I Googled and looks like many Android devices have some "advanced" settings including DNS server addresses. I can't find anything like that in Desire S. What am I doing wrong? How do I change DNS and IP settings in Desire S?