I've been trying to setup and test using Nis Netgroups as a means of access control, and have run into some difficulties. I have two client systems (ldap01, ldap02) setup to authenticate against an ldap database. Pam_Ldap and everything are setup and functioning as they should with respect to allowing users queried from the ldap database to login. Here are the relevant details. (I'm using this, btw http://directory.fedora.redhat.com/wiki/Howto:Netgroups ) [root at ldap02 security]# hostname ldap02.inside.exampledomain.com [root at ldap02 ~]# host ldap02.inside.exampledomain.com ldap02.inside.theplanet.com has address 10.5.1.17 [root at ldap02 ~]# host 10.5.1.17 17.1.5.10.in-addr.arpa domain name pointer ldap02.inside.exampledomain.com [root at ldap02 security]# getent netgroup unixisusers unixisusers ( , mmontgomery, ) [root at ldap02 security]# getent netgroup unixissystems unixissystems (ldap01, , inside.exampledomain.com) (ldap02, , inside.exampledomain.com) [root at ldap02 security]# id mmontgomery uid=1000(mmontgomery) gid=10000(UnixIS) groups=10000(UnixIS) [root at ldap02 security]# tail access.conf | grep -v '#' + : root : LOCAL + : mmont : ALL + : @unixisusers@@unixissystems : ALL - : ALL : ALL [root at ldap02 pam.d]# cat system-auth #%PAM-1.0 # This file is auto-generated. # User changes will be destroyed the next time authconfig is run. auth required /lib/security/$ISA/pam_env.so auth sufficient /lib/security/$ISA/pam_unix.so likeauth nullok auth sufficient /lib/security/$ISA/pam_ldap.so use_first_pass auth required /lib/security/$ISA/pam_deny.so account required /lib/security/$ISA/pam_unix.so account required /lib/security/$ISA/pam_access.so account sufficient /lib/security/$ISA/pam_succeed_if.so uid < 100 quiet account [default=bad success=ok user_unknown=ignore] /lib/security/$ISA/pam_ldap.so account required /lib/security/$ISA/pam_permit.so password requisite /lib/security/$ISA/pam_cracklib.so retry=3 password sufficient /lib/security/$ISA/pam_unix.so nullok use_authtok md5 shadow password sufficient /lib/security/$ISA/pam_ldap.so use_authtok password required /lib/security/$ISA/pam_deny.so session required /lib/security/$ISA/pam_limits.so session required /lib/security/$ISA/pam_unix.so session required /lib/security/$ISA/pam_mkhomedir.so skel=/etc/skel umask=077 session optional /lib/security/$ISA/pam_ldap.so When trying to login remotely, I get this: /var/log/messages: Jan 9 16:17:19 ldap02 pam_access[1552]: access denied for user `mmontgomery' from `202.10-5-1.inside.exampledomain.com' Adding this to access.conf, makes it work though: + : @unixisusers : ALL Does anyone have any ideas what I'm overlooking here? Thanks