On Fri, Sep 9, 2022 at 11:36 PM Andrea Pappacoda <and...@pappacoda.it> wrote:
> Il giorno ven 9 set 2022 alle 12:17:42 -05:00:00, Greg Oliver > <oliver.g...@gmail.com> ha scritto: > > Well, easiest to explain is user apps that use tcp or udp sockets to > > communicate. If they are on the same host, then huge gains can be > > achieved by using the loopback adapter (especially TCP comms). > > Thanks, but again, is this related to systemd-network in any way? My > question is whether letting systemd-network manage the loopback > interface is useful or not, not what the loopback interface is used for > in general. > > As far as I understand, systemd itself brings up the loopback interface > on its own during the early boot stage, and systemd-network(d) is > launched much later. But is writing something like this in > /etc/systemd/network/foo.conf ever useful? > > $ cat /etc/systemd/network/foo.conf > [Match] > Name=* > Type=loopback > It's useful when you want the `lo` interface to have a custom [Address] or two. Routers often have an address assigned that's supposed to be independent from any "physical" interface – on Linux it could be assigned to a Type=dummy interface or to an empty bridge, but just as frequently it's assigned to `lo`. (It's even called a "loopback address".) -- Mantas Mikulėnas
