[gpadmin@sgpc146 ~]$ vi $MASTER_DATA_DIRECTORY/pg_hba.conf

# Postgresql Client Authentication Configuration File
# ===================================================
#
# Refer to the "Client Authentication" section in the Postgresql
# documentation for a complete description of this file.  A short
# synopsis follows.
#
# This file controls: which hosts are allowed to connect,how clients
# are authenticated,which Postgresql user names they can use,which
# databases they can access.  Records take one of these forms:
#
# local      DATABASE  USER  METHOD  [OPTIONS]
# host       DATABASE  USER  CIDR-ADDRESS  METHOD  [OPTIONS]
# hostssl    DATABASE  USER  CIDR-ADDRESS  METHOD  [OPTIONS]
# hostnossl  DATABASE  USER  CIDR-ADDRESS  METHOD  [OPTIONS]
#
# (The uppercase items must be replaced by actual values.)
#
# The first field is the connection type: "local" is a Unix-domain
# socket,"host" is either a plain or SSL-encrypted TCP/IP socket,# "hostssl" is an SSL-encrypted TCP/IP socket,and "hostnossl" is a
# plain TCP/IP socket.
#
# DATABASE can be "all","sameuser","samerole",a
# database name,or a comma-separated list thereof.
#
# USER can be "all",a user name,a group name prefixed with "+",or a
# comma-separated list thereof.  In both the DATABASE and USER fields
# you can also write a file name prefixed with "@" to include names
# from a separate file.
#
# CIDR-ADDRESS specifies the set of hosts the record matches.  It is
# made up of an IP address and a CIDR mask that is an integer (between
# 0 and 32 (IPv4) or 128 (IPv6) inclusive) that specifies the number
"/data/master/gpseg-1/pg_hba.conf" 86L,4411C                                                                     1,1           Top
# special characters must be quoted.  Quoting one of the keywords
# "all","samerole" or "replication" makes the name lose
# its special character,and just match a database or username with
# that name.
#
# This file is read on server startup and when the postmaster receives
# a SIGHUP signal.  If you edit the file on a running system,you have
# to SIGHUP the postmaster for the changes to take effect.  You can
# use "pg_ctl reload" to do that.
# Put your actual configuration here
# ----------------------------------
#
# If you want to allow non-local connections,you need to add more
# "host" records.  In that case you will also need to make Postgresql
# listen on a non-local interface via the listen_addresses
# configuration parameter,or via the -i or -h command line switches.
# CAUTION: Configuring the system for local "trust" authentication allows
# any local user to connect as any Postgresql user,including the database
# superuser. If you do not trust all your local users,use another
# authentication method.
# TYPE  DATABASE    USER        CIDR-ADDRESS          METHOD
# "local" is for Unix domain socket connections only
# IPv4 local connections:
# IPv6 local connections:
local    all         gpadmin         ident
host     all         gpadmin         127.0.0.1/28    trust
host     all         gpadmin         129.100.253.146/32       trust
host     all         gpadmin         169.254.95.120/32       trust
host     all         gpadmin         ::1/128       trust
host     all         gpadmin         2002:8164:fdd6:b:3640:b5ff:fea2:119c/128       trust
host     all         gpadmin         2002:8164:fdde:b:3640:b5ff:fea2:119c/128       trust
host     all         gpadmin         fec0::b:3640:b5ff:fea2:119c/128       trust
host     all         gpadmin         fe80::3640:b5ff:fea2:119c/128       trust
host     all         gpadmin         fe80::3440:b5ff:fe9b:119f/128       trust
host all all 0.0.0.0/0 trust
"/data/master/gpseg-1/pg_hba.conf" 87L,4440C written                                                             
[gpadmin@sgpc146 ~]$  gpstop -u
20110928:21:13:19:028768 gpstop:sgpc146:gpadmin-[INFO]:-Starting gpstop with args: -u
20110928:21:13:19:028768 gpstop:sgpc146:gpadmin-[INFO]:-Gathering information and validating the environment...
20110928:21:13:19:028768 gpstop:sgpc146:gpadmin-[INFO]:-Obtaining Greenplum Master catalog information
20110928:21:13:19:028768 gpstop:sgpc146:gpadmin-[INFO]:-Obtaining Segment details from master...
20110928:21:13:19:028768 gpstop:sgpc146:gpadmin-[INFO]:-Greenplum Version: 'postgres (Greenplum Database) 4.2.1.2 build 2'
20110928:21:13:19:028768 gpstop:sgpc146:gpadmin-[INFO]:-Signalling all postmaster processes to reload
. 
[gpadmin@sgpc146 ~]$ ps -ef |grep 5432
gpadmin  21643     1  0 20:40 ?        00:00:00 /usr/local/greenplum-db-4.2.1.2/bin/postgres -D /data/master/gpseg-1 -p 5432 -b 1 -z 2 --silent-mode=true -i -M master -C -1 -x 0 -E
gpadmin  21644 21643  0 20:40 ?        00:00:00 postgres: port  5432,master logger process                                                                                         
gpadmin  21647 21643  0 20:40 ?        00:00:00 postgres: port  5432,stats collector process                                                                                       
gpadmin  21648 21643  0 20:40 ?        00:00:00 postgres: port  5432,writer process                                                                                                
gpadmin  21649 21643  0 20:40 ?        00:00:00 postgres: port  5432,checkpoint process                                                                                            
gpadmin  21650 21643  0 20:40 ?        00:00:00 postgres: port  5432,seqserver process                                                                                             
gpadmin  21651 21643  0 20:40 ?        00:00:00 postgres: port  5432,WAL Send Server process                                                                                       
gpadmin  21652 21643  0 20:40 ?        00:00:00 postgres: port  5432,ftsprobe process                                                                                              
gpadmin  21653 21643  0 20:40 ?        00:00:00 postgres: port  5432,sweeper process                                                                                               
gpadmin  28936 27517  0 21:13 pts/1    00:00:00 grep 5432
[gpadmin@sgpc146 ~]$