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Archive for January, 2011

POSTFIX was already installed in a simple fashion using real Unix accounts. We will continue to use these Unix accounts but pass authentication duties off to an LDAP server.

I used the Centos Directory Server and it was necessary to install the (75misc.ldif schema in the server to allow for mail aliases and mailing lists).

/etc/postix/master.cf was not changed for this set-up.

The following settings were placed in
/etc/postfix/main.cf:

queue_directory = /var/spool/postfix
command_directory = /usr/sbin
daemon_directory = /usr/libexec/postfix
mail_owner = postfix
myhostname = vm239.example.com
mydomain = example.com
myorigin = $mydomain
inet_interfaces = all

mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain

unknown_local_recipient_reject_code = 550
mynetworks_style = subnet
#mynetworks = 10.200.3.0/24, 127.0.0.0/8

alias_maps = hash:/etc/aliases
alias_database = $alias_maps
local_recipient_maps = ldap:/etc/postfix/ldap-users.cf
home_mailbox = Maildir/
virtual_alias_maps = ldap:/etc/postfix/ldap-aliases.cf
newaliases_path = /usr/bin/newaliases.postfix

# Virtual Users
# I didn’t use this but it could be used
#

#virtual_mailbox_domains = virtual.com
#virtual_mailbox_base = /var/spool/virt_mailboxes/
#virtual_mailbox_maps = hash:/etc/postfix/vmailbox
#virtual_mailbox_maps = ldap:/etc/postfix/ldap-users.cf
#virtual_minimum_uid = 100
#virtual_uid_maps = static:500
#virtual_gid_maps = static:500
#virtual_alias_domains = virtual.com
#virtual_alias_maps = hash:/etc/postfix/valias

This was added to the bottom of the /etc/aliases file but otherwise it was left as installed (note: run the newaliases command after any changes are made to the aliases file).

root: tedc

/etc/postfix/ldap-users.cf

bind = no
version = 3
timeout = 20
size_limit = 1
expansion_limit = 0
start_tls = no
tls_require_cert = no
server_host = ldap://vm241.example.com/
scope = sub
search_base = ou=people,dc=example,dc=com
query_filter = (mail=%s)
result_attribute = uid

/etc/ldap-aliases.cf

bind = no
timeout = 20
server_host = ldap://vm241.example.com
search_base = ou=aliases,dc=example,dc=com
scope = sub
version = 3
query_filter = (cn=%s)
result_attribute = rfc822MailMember

Ask any Linux geek which is the best Window Manager and you can easily find yourself in the middle of a holy war but ask a Windows user the same question and you will be met with a blank stare. Window Managers are one of those wild and wonderful features of Linux that can completely change your experience with your computer.

To either change you Window Manager (in Ubuntu) or even to just see which one is currently the default you need to look at the file:

/etc/X11/default-display-manager

It would show for GNOME:
/usr/sbin/gdm

and for KDE:
/usr/lib/kde4/bin/kdm

There are a wide variety of other possibilities of course but those are the two big ones.

To change the Window Manager open a terminal and type:

sudo dpkg-reconfigure gdm

NOTE: the WM configuration files are different for other Linux distributions and yes, I agree, that should be standardized.