This is kept at: /afs/slac/g/www/www-iepm/pinger/beacons-pingervm.txt
It appears as:
#==================================================================================================
#Current as of: Fri Mar 6 12:20:03 2015
#Written by Script: /afs/slac/package/pinger/write_offsitenodes.pl for pinger. It works under account cottrell
# Beacons requirements: Monitoring site
# Beacons requirements: < 2% unreachability for several months
# Beacons requirements: interest to ESnet or HENP or ICFA/SCIC
# e.g. a Beacon could be in Particle Data Group (PDG) book, or a collaborator in major HENP experiment
# Beacons requirements: represents a community
# The current master list is kept at:
# http://www-iepm.slac.stanford.edu/pinger/beacons.txt
#Location of Historical offsite.nodes: /afs/slac/g/scs/net/pinger/bin/offsite-nodes/offsite.nodes
#==================================================================================================
pinger.slac.stanford.edu 134.79.104.80 #[Beacon - Stanford Linear Accelerator Center]
#####################################################################
# Number of Beacons=1