Section 211. Pleadings, proof and motions

A matrimonial action shall be
  commenced by the filing of a  summons  with  the  notice  designated  in
  section  two  hundred  thirty-two  of  this  chapter,  or  a summons and
  verified complaint as provided in section  three  hundred  four  of  the
  civil  practice  law  and  rules.  A  final judgment shall be entered by
  default for want of appearance or pleading, or  by  consent,  only  upon
  competent  oral  proof or upon written proof that may be considered on a
  motion for summary judgment.  Where a complaint or  counterclaim  in  an
  action  for  divorce or separation charges adultery, the answer or reply
  thereto may  be  made  without  verifying  it,  except  that  an  answer
  containing  a counterclaim must be verified as to that counterclaim. All
  other pleadings in a matrimonial action shall be verified.