Autofs Home Directories

First, as root, you have to edit the file: /etc/auto.master to include the following line:

/home   /etc/auto.home  --timeout=60

Then, create a new file called /etc/auto.home, and add the following line in it:

*          -fstype=nfs,rw,nosuid,soft     server:/home/&

Troubleshooting

restore context of all files from an rpm

rpm -ql NAME | xargs restorecon -v

Squid

yuim install squid -y

chkconfig squid on

vim /etc/squid/squid.conf

Add
acl our_networks src 192.168.0.0/24
http_access allow our_networks
visible_hostname servername.example.com

Port
http_port 3128
Run
squid -z

IPTABLES

Redirect
iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-ports 3128
iptables -A RH-Firewall-1-INPUT -p tcp --dport 3128 -j ACCEPT

Standard
iptables -A RH-Firewall-1-INPUT -p tcp --dport 3128 -j ACCEPT


SELINUX
If changing squid port either add the port to selinux or set the squid_connect_any boolean

semanage port -a -t http_cache_port_t -p tcp PORTNUM
OR
setsebool -P squid_connect_any=1

Mail - Sendmail

yum groupinstall "Mail Server"

Setup
Comment out
DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl
FEATURE(`accept_unresolvable_domains')dnl

Masquerade
MASQUERADE_AS(`mydomain.com')dnl

Access
Reject     - error message
Discard   - no error
Relay

Example
# by default we allow relaying from localhost...
Connect:localhost.localdomain           RELAY
Connect:localhost                       RELAY
Connect:127.0.0.1                       RELAY
Connect:127.0.0.1                       RELAY
From:example.net                        REJECT
Connect:example.net                     REJECT
From:user@domain.com              DISCARD

Domaintable
Allows you to map to different domains
the following will forward from example.com to example.org
example.com    example.org

Virtusertable
root@example.com                root
postmaster@example.com          postmaster@noc.example.net
@example.com                    joe

Dovecot

IPTables Ports
If in doubt check /etc/services

pop3 110/tcp      
pop3 110/udp
imap 143/tcp
imap 143/udp

pop3s 995/tcp      
pop3s 995/udp
imaps 993/tcp
imaps 993/udp

Lock dovecot down to specific users
# vim  /etc/pam.d/dovecot
#%PAM-1.0
auth       required     pam_nologin.so
auth       required     pam_listfile.so item=user sense=allow file=/etc/dovecot_users onerr=fail
auth       include      system-auth
account    include      system-auth
session    include      system-auth

Testing dovecot
mutt -f imaps://user@server

IP TABLES

Masquerading

Configure Firewall
iptables -t nat -A POSTROUTING -s <internal subnet>-o <outbound interface> -j MASQUERADE

You will also have to allow the services that you want to provide to the internal network

iptables -A INPUT -s <internal subnet> -p <protocol> --dport <port number> -j ACCEPT

iptables -A INPUT -s 192.168.190.0/24 -p tcp --dport 21 -j ACCEPT

Setup Routing
edit /etc/sysctl.conf
net.ipv4.ip_forward = 1
sysctl -p

X WINDOWS

Install
yum groupinstall "X Window System"

Configure
chkconfig xfs on
service xfs start

system-config-display

test config creation
Xorg -probeonly

create config file in console
Xorg -configure

Run remote X apps
ssh -X user@server

Desktop Managers
yum install switchdesk

Troubleshooting

Logs
/var/log/Xorg.0.log
~.xsession-errors
/var/log/messages

Display not set
export DISPLAY=localhost:0.0
or
export DISPLAY=:0.0

xfs not running - check /tmp or /home to see if they are full

corrupt XFS sconfig - reintall xfs rpm?
rpm -ivh --force xorg*xfs*

TCP_WRAPPERS

syntax
<daemon list> : <client list> [except <client list>] [: <option>]


.example.com                            - anyone from example domain
192.168.190.                            - any ip from the 192.168.190.0 network
192.168.190.0/255.255.255.0  - any ip from the 192.168.190.0 network
ALL                                          - Anyone
user@computer                         - user from specific computer

Lookup Order
1./etc/hosts.allow
2./etc/hosts.deny
3.allow by default