One problem with changing "client ipc signing" is that it is not documented in the man pages of these packages for Ubuntu 12.04 and the settings are different to the Samba packages in Ubuntu 14.04 (where the possible settings are "auto", "mandatory" and "disabled").
One problem with changing "client ipc signing" is that it is not documented in the man pages of these packages for Ubuntu 12.04 and the settings are different to the Samba packages in Ubuntu 14.04 (where the possible settings are "auto", "mandatory" and "disabled").