can't install zlib/libz

Hello,

I'm on opensuse 13.1, and I'm in the process of installing openssh.

But, when I run the opensuse "configure" , I get:
...
checking...
configure: error: *** zlib missing - please install first ***

So, I tried to install zlib, but I get :

>rpm -i zlib-1.2.5_git201105272030-20.1.4.x86_64.rpm
error: Failed dependencies:
zlib < 1.2.8-3.1.2 is obsoleted by (installed) libz1-1.2.8-3.1.2.x86_64

I tried to find the libz command , but no luck.
I did see the libz.so files in /lib64 , but I can't find the rpm that it seems to say is already installed.
How does one install zlib ?

Thanks