The Jargon File (version 4.4.7, 29 Dec 2003):

breath-of-life packet
 n.

    [XEROX PARC] An Ethernet packet that contains bootstrap (see boot) code,
    periodically sent out from a working computer to infuse the ?breath of
    life? into any computer on the network that has happened to crash. Machines
    depending on such packets have sufficient hardware or firmware code to wait
    for (or request) such a packet during the reboot process. See also 
    dickless workstation.

    The notional kiss-of-death packet, with a function complementary to that of
    a breath-of-life packet, is recommended for dealing with hosts that consume
    too many network resources. Though ?kiss-of-death packet? is usually used
    in jest, there is at least one documented instance of an Internet subnet
    with limited address-table slots in a gateway machine in which such packets
    were routinely used to compete for slots, rather like Christmas shoppers
    competing for scarce parking spaces.


The Free On-line Dictionary of Computing (30 December 2018):

breath-of-life packet

   (XEROX PARC) An Ethernet packet that contains
   bootstrap code, periodically sent out from a working
   computer to infuse the "breath of life" into any computer on
   the network that has crashed.  Computers depending on such
   packets have sufficient hardware or firmware code to wait for
   (or request) such a packet during the reboot process.

   See also dickless workstation.

   The notional "kiss-of-death packet", with a function
   complementary to that of a breath-of-life packet, is
   recommended for dealing with hosts that consume too many
   network resources.  Though "kiss-of-death packet" is usually
   used in jest, there is at least one documented instance of an
   Internet subnet with limited address-table slots in a
   gateway computer in which such packets were routinely used to
   compete for slots, rather like Christmas shoppers competing
   for scarce parking spaces.

   [Jargon File]

   (1995-01-26)