[CentOS] environment variables in kickstart

I have been looking for environment variables for the %post section of 
kickstart.

Namely if I start my kickstart command with "linux 
ks=http://serverip/ks.cfg"
is there an environment variable that has serverip that I can use in the 
%post section?

Also is there a way to pass a command line argument to the %post section 
when running
kickstart command as the above http://serverip/ks.cfg

Thanks,

Jerry