when i try to connect my nokia n9 to a wifi connection it says “internet connection failed.cannot able to get ip address from DHCP server ”

please help me out

I had the same problem but this happened cause my router had static ip check your modem if the ip is static.

yeah i checked . my router has a static ip address only . still am not able to connect

I also had this issue when using my wireless N router. I switched to wireless G and the issue went away.

omg u want me to change the router for this :O :P

Well... that's your problem... You know what DHCP is right?
If the DHCP host/server isn't enabled (only static), then the N9's WiFi adapter won't be assigned an IP.

Why? Because according to your 1st post, it's expecting to be assigned an IP address that way.
“internet connection failed.cannot able to get ip address from DHCP server ”

You could also statically assign the N9's IP on the router, & then manually enter that address into the N9's wifi settings*
Get someone that's more clued-up about local networking to check your router & your N9 config.

*no idea if N9 does static IP addresses, DHCP, or both, possibly it does both.

jalyst ....
I just got my n9, and i also have a dual band router. -and i get very minImal signal, especially under 5ghZ, it keep connecting ,disconnecting.
No errors , just very bad signal, my n900 can connect to 2.4 from outside, n9 cant even get one bar . Its a significant difference,
And easy to tell that there a wifi issue with the phone
Can anyone help me

No issue here, actually I think the WiFi reception is very good all through the house.
At the office i am near the router, so cannot say anything about it.
But I have not tried the City Wimax yet.

I have a wireless-n Apple router (Airport Express) and it works fine with it. The N9 does have a real problem switching back to cellular data after it has been on wifi though. Seems I have to manually connect each time. And the wifi signal is not nearly as good as the N900 (and the N800 is hands down the best, most sensitive wifi device I have ever used--so Nokia is really losing on this one).

I think it is just setting an option in the router to enable DHCP. If you can get into the router setup you should be able to do it.