[Samba] rpc_pipe_open_ncalrpc: connect(/run/samba/ncalrpc/EPMAPPER) failed: No such file or directory

[Andrew Bartlett]

On Mon, 2023-10-02 at 20:27 +0300, Michael Tokarev via samba wrote:
> 02.10.2023 15:22, Norbert Hanke via samba:
> > on two of my DCs:
> > 
> >  > samba -V
> > Version 4.17.10-Debian
> >  > file /run/samba/ncalrpc/EPMAPPER
> > /run/samba/ncalrpc/EPMAPPER: socket
> 
> Yes, this socket does exist on a DC. It is being listened
> by "samba: task[rpc] pre-forked worker(0)".
> 
> It does not exist on a member server, where I observe these
> log messages.
> 
> Here, on a member server, samba-dcerpc is being started and
> exited numerous times, each time logging a warning about it
> being unable to connect to /run/samba/ncalrpc/EPMAPPER - which
> does not exist on a member server.
> 
> /run/samba/ncalrpc/np/epmapper socket is being listened by
> samba-dcerpc itself.  So these are two different sockets.
> 
> Instead of observing the behavour and guessing, I'd love to
> know how things *should* work.

Sorry for not replying at the time.  My answer is clearer after the
recent security patches are public.

Samba's smbd will try to find an existing endpoint mapper to confirm if
the AD DC is running, to avoid starting services that would be
duplicate.

We now just work based on the smb.conf mode we are in, because
confirming with the endpoint mapper was subject to failure if the
server was busy.

The behaviour with the samba-dcerpcd starting and stopping is
intentional, unless configured as its own systemd service, because it
tries to be similar to the previous 'library in smbd' appraoch, and not
keep running forever after the last request ends.

Andrew Bartlett
-- 
Andrew Bartlett (he/him)       https://samba.org/~abartlet/
Samba Team Member (since 2001) https://samba.org
Samba Team Lead                https://catalyst.net.nz/services/samba
Catalyst.Net Ltd

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