00345    a2200121   4500020001500000082001500015100002500030245006300055260004300118300002000161650001800181700002400199  a0201633574  a005.8bCHE  aCheswick, William R.  aFirewalls and internet securitybRepelling the wily hacker  aNew YorkbAddison - Wesleyc1994g1994  axiv,306p.c23cm  aData security  aBellovin, Steven M.