This doesn't work in rhel6 indeed. NetworkManager doesn't expose "next-server" dhcp setting in Options property of org.freedesktop.NetworkManager.DHCP4Config. Why Dan? Is it a bug or is it intentional?

Also there might be a typo in anaconda code, but it is irrelevant now because neither server_name, nor next_server or any similar option is in Options.

--- a/loader/nfsinstall.c
+++ b/loader/nfsinstall.c
@@ -476,7 +476,7 @@ int getFileFromNfs(char * url, char * dest, struct loaderData_s * loaderData) {
                 continue;
             }
 
-            server_name = nm_dhcp4_config_get_one_option(dhcp, "server_name");
+            server_name = nm_dhcp4_config_get_one_option(dhcp, "next_server");
             if (!server_name) {
                 logMessage(ERROR, "no bootserver was found");
                 g_object_unref(client);

FYI, the exact same problem also happens with Fedora 14.
Fedora 3 and 5 worked with the "next-server" option (as documented
in the kickstart pages) without a problem.

An alternate solution that worked for me was to add a "server-name"
statement to the DHCP server config, eg:

 group {
  next-server 1.2.3.4;
  server-name "1.2.3.4";     <<<<<<<<<
  ...
  host x1 {
    filename "/kickstart/x1.ks";
    ...
  }
 }

(In reply to comment #3)
> FYI, the exact same problem also happens with Fedora 14.
> Fedora 3 and 5 worked with the "next-server" option (as documented
> in the kickstart pages) without a problem.
> 
> An alternate solution that worked for me was to add a "server-name"
> statement to the DHCP server config, eg:
> 
>  group {
>   next-server 1.2.3.4;
>   server-name "1.2.3.4";     <<<<<<<<<
>   ...
>   host x1 {
>     filename "/kickstart/x1.ks";
>     ...
>   }
>  }
Thanks for the information.

With transition from libdhcp to NetworkManager anaconda doesn't have access to next-server parameter. It is using server-name option instead. We need to update the documentation accordingly.

This request was evaluated by Red Hat Product Management for inclusion
in a Red Hat Enterprise Linux maintenance release. Product Management has 
requested further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed 
products. This request is not yet committed for inclusion in an Update release.

*** Bug 719359 has been marked as a duplicate of this bug. ***

Docs team,

Please see comment #4 for a summary of what needs changing.

I think we should change these parts of installation guide

32.10. Starting a Kickstart Installation, option ks, first paragraph:

"If ks is used alone, the installation program configures the Ethernet card to use DHCP. The kickstart file is read from the "bootServer" from the DHCP response as if it is an NFS server sharing the kickstart file. By default, the bootServer is the same as the DHCP server. The name of the kickstart file is one of the following:"

should be changed to:

"If ks is used alone, the installation program configures the Ethernet card to use DHCP. The kickstart file is read from NFS server specified by DHCP option server-name. The name of the kickstart file is one of the following:"

I am cloning the bug to update also Migration Guide.