The Perfect Server - CentOS 5.7 x86_64 [ISPConfig 2] - Page 3

4 Adjust /etc/hosts

Next we edit /etc/hosts. Make it look like this:

vi /etc/hosts

# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1               localhost.localdomain localhost
192.168.0.100           server1.example.com server1
::1             localhost6.localdomain6 localhost6

5 Configure Additional IP Addresses

(This section is totally optional. It just shows how to add additional IP addresses to your network interface eth0 if you need more than one IP address. If you're fine with one IP address, you can skip this section.)

Let's assume our network interface is eth0. Then there is a file /etc/sysconfig/network-scripts/ifcfg-eth0 which contains the settings for eth0. We can use this as a sample for our new virtual network interface eth0:0:

cp /etc/sysconfig/network-scripts/ifcfg-eth0 /etc/sysconfig/network-scripts/ifcfg-eth0:0

Now we want to use the IP address 192.168.0.101 on the virtual interface eth0:0. Therefore we open the file /etc/sysconfig/network-scripts/ifcfg-eth0:0 and modify it as follows (we can leave out the HWADDR line as it is the same physical network card):

vi /etc/sysconfig/network-scripts/ifcfg-eth0:0

# Intel Corporation 82545EM Gigabit Ethernet Controller (Copper)
DEVICE=eth0:0
BOOTPROTO=static
BROADCAST=192.168.0.255
IPADDR=192.168.0.101
NETMASK=255.255.255.0
NETWORK=192.168.0.0
ONBOOT=yes

Afterwards we have to restart the network:

/etc/init.d/network restart

You might also want to adjust /etc/hosts after you have added new IP addresses, although this is not necessary.

Now run

ifconfig

You should now see your new IP address in the output:

[root@server1 ~]# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:0C:29:89:71:35
          inet addr:192.168.0.100  Bcast:192.168.0.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:307 errors:0 dropped:0 overruns:0 frame:0
          TX packets:251 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:29217 (28.5 KiB)  TX bytes:45961 (44.8 KiB)

eth0:0    Link encap:Ethernet  HWaddr 00:0C:29:89:71:35
          inet addr:192.168.0.101  Bcast:192.168.0.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:8 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:560 (560.0 b)  TX bytes:560 (560.0 b)

[root@server1 ~]#

6 Disable The Firewall And SELinux

(You can skip this chapter if you have already disabled the firewall and SELinux at the end of the basic system installation (in the Setup Agent).)

I want to install ISPConfig at the end of this tutorial which comes with its own firewall. That's why I disable the default CentOS firewall now. Of course, you are free to leave it on and configure it to your needs (but then you shouldn't use any other firewall later on as it will most probably interfere with the CentOS firewall).

SELinux is a security extension of CentOS that should provide extended security. In my opinion you don't need it to configure a secure system, and it usually causes more problems than advantages (think of it after you have done a week of trouble-shooting because some service wasn't working as expected, and then you find out that everything was ok, only SELinux was causing the problem). Therefore I disable it, too (this is a must if you want to install ISPConfig later on).

Run

system-config-securitylevel

Set both Security Level and SELinux to Disabled and hit OK:

Afterwards we must reboot the system:

reboot

7 Install Some Software

First we import the GPG keys for software packages:

rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY*

Then we update our existing packages on the system:

yum update

Now we install some software packages that are needed later on:

yum install fetchmail wget bzip2 unzip zip nmap openssl lynx fileutils gcc gcc-c++

8 Quota

(If you have chosen a different partitioning scheme than I did, you must adjust this chapter so that quota applies to the partitions where you need it.)

To install quota, we run this command:

yum install quota

Edit /etc/fstab and add ,usrquota,grpquota to the / partition (/dev/VolGroup00/LogVol00):

vi /etc/fstab

/dev/VolGroup00/LogVol00 /                       ext3    defaults,usrquota,grpquota        1 1
LABEL=/boot             /boot                   ext3    defaults        1 2
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
/dev/VolGroup00/LogVol01 swap                    swap    defaults        0 0

Then run

touch /aquota.user /aquota.group
chmod 600 /aquota.*
mount -o remount /
quotacheck -avugm
quotaon -avug

to enable quota.

9 Install A Chrooted DNS Server (BIND9)

To install a chrooted BIND9, we do this:

yum install bind-chroot

Then do this:

chmod 755 /var/named/
chmod 775 /var/named/chroot/
chmod 775 /var/named/chroot/var/
chmod 775 /var/named/chroot/var/named/
chmod 775 /var/named/chroot/var/run/
chmod 777 /var/named/chroot/var/run/named/
cd /var/named/chroot/var/named/
ln -s ../../ chroot
cp /usr/share/doc/bind-9.3.6/sample/var/named/named.local /var/named/chroot/var/named/named.local
cp /usr/share/doc/bind-9.3.6/sample/var/named/named.root /var/named/chroot/var/named/named.root
touch /var/named/chroot/etc/named.conf
chkconfig --levels 235 named on
/etc/init.d/named start

BIND will run in a chroot jail under /var/named/chroot/var/named/. I will use ISPConfig to configure BIND (zones, etc.).

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