Fix next-server behavior

guides/common/modules/con_dhcp-options.adoc

@@ -18,15 +18,8 @@ Each TFTP {SmartProxy} then reports this setting through the API and {Project} c
 
 When the PXE loader is set to `none`, {Project} does not populate the `next-server` option into the DHCP record.
 
-If the `next-server` option remains undefined, {Project} uses reverse DNS search to find a TFTP server address to assign, but you might encounter the following problems:
-
-* DNS timeouts during provisioning
-* Querying of incorrect DNS server.
-For example, authoritative rather than caching
-* Errors about incorrect IP address for the TFTP server.
-For example, `PTR record was invalid`
-
-If you encounter these problems, check the DNS setup on both {Project} and {SmartProxy}, specifically the PTR record resolution.
+If the `next-server` option remains undefined, {Project} calls the {SmartProxy} API to retrieve the server name as specified by the `--foreman-proxy-tftp-servername` argument in a `{foreman-installer}` run.
+If the {SmartProxy} API call does not return a server name, {Project} uses the hostname of the {SmartProxy}.
 
 .The filename option
 The `filename` option contains the full path to the file that downloads and executes during provisioning.