PREUN

/bin/sh

[ $1 = 0 ] && update-alternatives --remove mount.cifs /bin/mount.cifs3 ||:

POSTIN

/bin/sh

update-alternatives --install /bin/mount.cifs mount.cifs \
/bin/mount.cifs3 10 \
--slave /sbin/mount.cifs smount.cifs /sbin/mount.cifs3 \
|| update-alternatives --auto mount.cifs

Triggers

samba-client < 3.0.11-1mdk

/bin/sh

update-alternatives --auto mount.cifs