Wrong IP loopback interface -> scsynth not reachable


I’m new to this forum, used to read the maillists years ago, so excuse me if this isn’t
the proper place.

Under some (unknown to me) circumstances I get the following with startup and recompiling the classlib:

^^ The preceding error dump is for ERROR: Primitive ‘_NetAddr_SendMsg’ failed.
caught exception ‘send_to: Can’t assign requested address’ in primitive in method NetAddr:sendMsg
RECEIVER: a NetAddr(, 57110)

If I check with e.g.
$ ifconfig lo0 | grep "inet "


I can see the loopback interface has an improper IP address,
which seems a remnant from some LAN
I can fix it with:

$ sudo ifconfig lo0

This is on a M1 mac. It may be something in my class library, I don’t see anything obvious, and it persists when running SC with just the standard library.
Only re-setting the IP works.

As scsynth is not reachable, it is a showstopper. And the above is a temporary fix; the problem does re-appear, though not so often.

I wonder if others encountered this as well, if someone found out what’s the actual culprit.


jan kees