We have a configuration where we'd like to run a single cobbler instance, but we have nodes that are widely distributed across network links of varying quality. We need to (and do) host the initial boot image files locally for those subnets.

What I'd like to do is find a way to tag those subnets by name so that new systems, when they get added, get told that their next-server at the group level is our main cobbler server, but their initial next-server at the system level is the host for the boot files. Here's how one looks right now, and it does work this way:

dhcp.template (partial)

#for dhcp_tag in $dhcp_tags.keys():
:
group {
    next-server    $next_server:
    host $iface.name {
    :
        #if $dhcp_tag == "site1"
        next-server    192.168.43.18;
        #end if
:

What I'd _like_ to do, instead of expanding that "if $dhcp_tag ==" bit, is to replace it with something like:

            next-server      $iface.next-server;

But I have no idea how to influence the value of $iface.next-server. Where does that come from and how do I set it? It's referenced elsewhere in dhcp.template, and it appears to be part of the output of cobbler system dumpvars