On Fri, Sep 9, 2022 at 11:36 PM Andrea Pappacoda <andrea@xxxxxxxxxxxx> wrote:
Il giorno ven 9 set 2022 alle 12:17:42 -05:00:00, Greg Oliver
<oliver.greg@xxxxxxxxx> 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
