diff -rupN cobbler-2.0.11.old/cobbler/action_buildiso.py cobbler-2.0.11/cobbler/action_buildiso.py

--- cobbler-2.0.11.old/cobbler/action_buildiso.py	2015-06-11 18:48:59.000000000 +0200

+++ cobbler-2.0.11/cobbler/action_buildiso.py.new	2015-06-17 13:33:13.392123548 +0200

@@ -253,7 +253,14 @@ class BuildIso:

                        append_line = append_line + " gateway=%s" % data["gateway"]

                    if not exclude_dns and data.has_key("name_servers") and data["name_servers"]:

-                       append_line = append_line + " dns=%s\n" % ",".join(data["name_servers"])

+                       version = dist.os_version

+                       if dist.breed == "redhat" and (

+                           (version.startswith("rhel") and version >= "rhel7") or

+                           (version.startswith("fedora") and version >= "fedora17")

+                       ):

+                           append_line = append_line + " nameserver=%s\n" % " nameserver=".join(data["name_servers"])

+                       else:

+                           append_line = append_line + " dns=%s\n" % ",".join(data["name_servers"])

                    length=len(append_line)

                    if length > 254: