Set network interfaces order

[jacopo_pulici]

Hi all,
I'm facing an issue for the Macs of my company.
I need to set up the network service order for the different interfaces.
The main goal is to setup the interfaces as follow:
1- Ethernet (built in, Thunderbolt or USB)
2- Wifi
Basically I need to set up as primary interface any Eth connection detected and as secondary the Wifi. All the others can follow.

Does anyone has a solution/suggestion for this?
Thanks everybody.

Cheers,
Jack

[jrwilcox · Accepted solution]

That should be the default for OS X.

[jrwilcox · Accepted solution]

That should be the default for OS X.

[nessts]

I have a perl function that does it like this... If we are using the internal VPN and have named a service with VPN in the name it will put VPN first, Ethernet second and Wi-Fi last. And I believe you are incorrect @jrwilcox on all of the new models that do not have a built in Ethernet, Wi-Fi is en0 and tends to get sorted to the top, but, as I do not build stock machines very often and I know my stuff is setting it I could be quite wrong as well.

sub setNetworkServiceOrder {
    my $netcmd = "networksetup";
    my $listarg = "-listnetworkserviceorder";
    my $setarg = "-ordernetworkservices";
    my @disabled;
    my @hdw;
    my @vpns;
    open N, "$netcmd $listarg |", or die "$progname: list $!
";
    while (<N>) {
        chomp;
        next if /^An asterisk/;
        next if /^$/;
        my $port =$_;
        my ($num, $interface) = (split " ", $port, 2);
        if ($interface =~ /s/) {
            $interface = ""$interface"";
        }
        if ($num =~ /*/) {
            push @disabled, $interface;
            my $tmpline = <N>;
        }
        else {
            my $tmpline = <N>;
            if (($tmpline =~ /IPSec/) || ($tmpline =~ /L2TP/)) {
            push @vpns, $interface;
        }
            else {
                if ($interface =~ /Ethernet/) {
                    unshift @hdw, $interface;
                }
                else {
                    push @hdw, $interface;
                }
            }
        }
    }
    close N;
    my $serviceorder = join " ", @vpns, @hdw, @disabled;
    syslog('notice', "Network Service Order: %s",$serviceorder);
    system("$netcmd $setarg $serviceorder");
    return;
}

[jrwilcox]

I think you should check when you plug in an ethernet adapter it will removed to the top of the list if there is link. I know it was designed this way and I don't think they have changed since I managed the Ethernet team at Apple.

[jacopo_pulici]

Thanks @jrwilcox .
Today I imaged a new machine and actually the Ethernet connection was above the Wifi.
If in the network service order the wifi is above the Eth, when I plug the cable the Eth remains below the Wifi.
Anyway, by default Eth is on top of Wifi therefore at the moment I'm fine with that.
Thanks again.
Cheers

Jack

[jrwilcox]

If it has not been changed by the user at some point and Ethernet gets a dhcp address it should have priority over wifi. You can actually check the default order System Preferences>Network Click on the gear in the lower right corner and select Set Service Order. That is the default service order if all devices have link and a dhcp address.

[nessts · Accepted solution]

I concur, created a new location and added two ethernet interfaces and they have higher priority than the wifi does. I put my stuff in place back in 10.5 or 10.6 timeframe and have not checked it since. Good job getting that right.