BrainwreckedTech: /* Networking */ Removed Network Interfaces Switching Names -- Network names are now en[x]p[y] in GNU/Linux. Changed reference from netcfg to netctl for Arch.

2014-01-07T08:51:27Z

Networking: Removed Network Interfaces Switching Names -- Network names are now en[x]p[y] in GNU/Linux. Changed reference from netcfg to netctl for Arch.

@@ Line 43: / Line 43: @@
 ===Networking===
 ====Starting Multiple Network Interfaces At Boot====
@@ Line 75: / Line 68: @@
     post-up [command]
-Arch does not use an equivalent of Debian's system.  By default, Arch will start dhcpcd which will try to assign all NICs with an IP address via DHCP.  If this is all you need, no further configuration is required.
+For Arch, use <tt>netctl</tt> to configure mutliple devices and bring them up during boot.
 ====MTU====

BrainwreckedTech: 1 revision

2014-01-06T01:52:15Z

1 revision

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The purpose of this article is to give an overview of not only the steps required to get a Linux server up an running, but some of the caveats you should consider before embarking on such an endeavor. This article tries to remain as distribution-agnostic as possible, though at this time it's really only written from the perspectives of Ubuntu and Arch Linux.

Before proceeding, it's recommended you read [[Installing A Server/Considerations|Considerations]]. This can save you some time and help you make informed choices before you make the plunge into operating a Linux server.

=Common Tasks=

==Install A Minimum Server==

Linux distros have different ways of accomplishing this, but what's needed for a Linux server is a bare-bones installation.

===Arch Linux===

By default, Arch Linux already installs a minimal system.

===Ubuntu===

When at the Ubuntu installer screen,

# highlight <tt>Install Ubuntu in text mode</tt>
# press <tt>[F6]</tt> for <tt>Other Options</tt>
# press <tt>[ESC]</tt> to back out.
# Change <tt>ubuntu.seed</tt> to <tt>ubuntu-server-minimal.seed</tt> in the <tt>Boot Options</tt> line.

==Partition The Hard Drive==

See [[Drive Partitioning]] for more information.

==Post-Installation Configuration==

===Update Mirrors===

====Arch====

By installing the <tt>reflector</tt> package, you can always get the best mirrors at the current point in time.

reflector -l 5 -c [country] --sort rate --save /etc/pacman.d/mirrorlist

Note that <tt>[country]</tt> is the full proper-case name, not a two- or three-letter abbreviation. To specify a country with spaces, use the back slash like this: <tt>United\ States</tt>.

====Ubuntu====

The only automatic selection of mirrors comes from the GUI <tt>synaptic</tt> program. Otherwise you will have to select a mirror by hand from [https://launchpad.net/ubuntu/+archivemirrors Launchpad] and modify <tt>/etc/apt/sources.list</tt> by hand.

===Networking===

====Network Interfaces Switching Names====

You can use a file in <tt>/etc/udev/rules.d</tt> to keep the interface names the same between boots. Debian-based distros create this file (<tt>70-persistent-net.rules</tt>) during install. Other distros (like Arch Linux) do not.

SUBSYSTEM=="net", ATTR{address}=="01:23:45:67:89:ab", NAME="lan0"
SUBSYSTEM=="net", ATTR{address}=="fe:dc:ba:98:76:54", NAME="lan1"

====Starting Multiple Network Interfaces At Boot====

Debian uses a file called <tt>/etc/network/interfaces</tt>. By default, only the interface used during install is configured. It is trivial to add more interfaces to this file.

# DHCP Example

auto eth0
iface eth0 inet dhcp
pre-up [command]
post-up [command]

# Static Example

auto eth0
iface eth0 inet static
address 192.168.1.n
network 192.168.1.0
netmask 255.255.255.0
gateway 192.168.1.n
broadcast 192.168.1.255
mtu [nnnn]
pre-up [command]
post-up [command]

Arch does not use an equivalent of Debian's system. By default, Arch will start dhcpcd which will try to assign all NICs with an IP address via DHCP. If this is all you need, no further configuration is required.

If you wish to bring up a single NIC with custom settings, the <tt>interface</tt> directive in the <tt>NETWORKING</tt> section of <tt>/etc/rc.conf</tt>.

# -----------------------------------------------------------------------
# NETWORKING
# -----------------------------------------------------------------------
...
HOSTNAME="[hostname]"
...
interface=eth0
address=192.168.1.2
netmask=255.255.255.0
gateway=192.168.1.1
broadcast=192.168.1.255
...
#NETWORKS=(main)

If you wish to bring up multiple interfaces which will be connected at boot time, use <tt>netcfg</tt> instead.

====MTU====

{{MTU}}

===Set Up Users===

sudo useradd -m -g users --uid [nnnn] [username]
sudo passwd [user]

==Install Common Programs==

===acpid / acpi-support===

To be able to turn the server off using the power button, install <tt>acpid</tt>.

Be sure the <tt>buttons</tt> module is loaded using <tt>lsmod | grep ^button</tt>.

For Arch Linux, be sure to add <tt>acpid</tt> to the <tt>DAEMONS</tt> array in <tt>/etc/rc.conf</tt> if you are not using <tt>hal</tt>.

===cpufreqd===

'''Not all Intel Atom Processors support SpeedStep. See [http://ark.intel.com/MySearch.aspx?s=t&SpeedstepTechnology=true&FamilyText=Intel%C2%AE%20Atom%E2%84%A2%20Processor Intel's List].'''

The latest Linux distros have the scaling CPU modules (<tt>speedstep_centrino</tt>, <tt>powernow_k6</tt>, <tt>powernow_k7</tt>, <tt>acpi_cpufreq</tt>) and the scaling governor modules (<tt>conservative</tt>, <tt>ondemand</tt>, <tt>userspace</tt>, <tt>perfomance</tt>, <tt>powersave</tt>) built into the kernel. You no longer have to fiddle around with <tt>modprobe</tt> and modules.

Configuration is handled through <tt>/etc/cpufreqd.conf</tt>. You may have to enable some of the <tt>[Profile]</tt> sections because <tt>cpufreqd.conf</tt> plays it too safe. You may also have to get rid of some <tt>[Rule]</tt> sections, like the one for playing movies which <tt>cpufreqd</tt> kept choosing it even though I had none of the listed programs installed let alone running.

===cpufrequtils===

This will provide <tt>cpufreq-info</tt>, which will give you information on how <tt>cpufreqd</tt> is governing your CPU.

===lm-ensors===

After installing this package, run <tt>sudo sensors-detect</tt> and answer yes to all questions. When finished, the program will offer to insert the appropriate modules into <tt>/etc/modules</tt>.

On Arch, you will have to manually add <tt>sensors</tt> the the <tt>DAEMONS</tt> array in <tt>/etc/rc.conf</tt>

===ntp===

NTP uses UDP port 123 to synchronize. If your ISP does not block ports (≤1024) you can use external NTP servers as-is. If your ISP does block ports, you can have the NTP server grab it's time from a time server with SNTP and then synchronize with itself.

Get your original synchronization before starting NTP:<br>
(run this command a few times until the offset settles down)

ntpd -qg &

Edit /etc/ntp.conf, remove the existing server line(s) and add the following lines to have the NTP server reference itself:

server 127.127.1.1
fudge 127.127.1.1 stratum 14 refid NIST

You'll also need to knock out the default restrict lines

restrict -4 default kod ...
restrict -6 default kod ...

Insert this line in those two previous lines' place

restrict default notrust nomodify

Make a crontab so we can keep our NTP server in line with time:

sudo nano /etc/cron.d/synctime

Put the following line in the file and save:<br>
(This calls a script that shuts ntp down, calls ntpdate, and then starts ntp again. It’s meant to be used when bringing network interfaces up, but there’s nothing wrong with calling on it here.)

* 4,8,12,16,20 * * * ntpd -qg

Restart the NTP server:

sudo /etc/init.d/ntp start

Watch the NTP server:

watch 'sh -c "ntpq -p && echo && ntpq -c as && echo && ntptrace"'

When you see the following parts, your NTP server is ready:

# at least one remote has an asterisk in front of its name
# poll is greater than 16
# condition changes to sys.peer
# stratum changes to less than 16

remote refid st t when poll reach delay offset jitter
==============================================================================
*LOCAL(1) .NIST. 14 l 30 64 17 0.000 0.000 0.001

ind assID status conf reach auth condition last_event cnt
===========================================================
1 47409 9614 yes yes none sys.peer reachable 1

localhost: stratum 15, offset 0.000000, synch distance 0.948602</pre>

===openssh-server===

This will allow you to remotely administer your server without having to be there physically.

For Arch, be sure to add <tt>sshd</tt> to the <tt>DAEMONS</tt> array in <tt>/etc/rc.conf</tt>.

===rsync===

You can use the <tt>rsync</tt> program to ease both the chore and space requirements of making backups. The following two commands will get you up and going with rolling updates using hard links. The net effect is that you will get a snapshot of whatever you are backing up of at whatever interval you decide to use and that only changed files take up additional space.

Make your initial backup with this command:

cp -av [source] `date +%F`

You can then make subsequent backups using the following command:

/usr/bin/rsync -a --delete --link-dest=`ls -1r [destination]|head -1` [source] `date +\%F`

=BitTorrent Server=

==transmission-cli==

After installation, <tt>tranmission-daemon</tt> might be up and running. To stop it:

/etc/init.d/transmission-daemon stop
- or -
/etc/rc.d/transmission-daemon stop

Here are some key settings you might wish to change:

"bind-address-ipv4": "[daemon-ip]",
"download-dir": "[download-dir]",
"incomplete-dir": "[incomplete-dir]",
"incomplete-dir-enabled": true,
"peer-port": [port],
"peer-port-random-on-start": false,
"rpc-authentication-required": true,
"rpc-bind-address": "[webgui-ip]",
"rpc-enabled": true,
"rpc-password": "[webgui-password]",
"rpc-port": [webgui-port],
"rpc-username": "[webgui-username]",
"rpc-whitelist": "[csv-ip-addresses-ranges]",
"rpc-whitelist-enabled": true,
"watch-dir": "[watch-dir]",
"watch-dir-enabled": true

Note that the current <tt>rpc-password</tt> is a hash. You can overwrite this with a plain-text password. When the daemon is started back up, it will replace the plain-text password with a hased version.

Settings not listed here can be changed in the web GUI.

=File Server Setup=

===nfs-kernel-server / nfs-utils===

Edit <tt>/etc/exports</tt> and add the appropriate line:

/home 192.168.1.0/255.255.255.0(rw,sync,no_subtree_check)

Then run this command to export the shares:

sudo exportfs -ra

===samba===

Be sure to add the first 3 lines in the <tt>[global]</tt> section in <tt>/etc/samba/smb.conf</tt> so that <tt>samba</tt> will follow symlinks around properly for Windows clients. The following assumes a setup that only shares files and does not provide WINS or domain services nor share printers or other devices. Only lines you should be interested in changing are listed here. There are more (that aren't related to said skipped services and shares) that you should in all likelyhood leave alone.

[global]

follow symlinks = yes
wide links = yes
unix extensions = no
use sendfile = yes

## Browsing/Identification ###

workgroup = [workgroup]
server string = [server-string]
wins support = no
dns proxy = no

#### Networking ####

interfaces = [interface]
bind interfaces only = yes

####### Authentication #######

security = user
encrypt passwords = true
map to guest = bad user

########## Domains ###########

domain logons = no

########## Printing ##########

load printers = no

############ Misc ############

socket options = TCP_NODELAY SO_RCVBUF=262144 SO_SNDBUF=262144
usershare max shares = 0
usershare allow guests = no

#======================= Share Definitions =======================

[homes]
comment = Home Directories
browseable = yes
read only = no
create mask = 0750
directory mask = 0750
valid users = %S

=LAMP Server Setup=

==apache2==

Ubuntu sets modules up in /etc/apache2/mods-available and sets up links in /etc/apache2/mods-enabled.

ln -s /etc/apache2/mods-available/vhost_alias.load /etc/apache2/mods-enabled/vhost_alias.load

Likewise, Ubuntu has a similar setup for sites with /etc/apache2/sites-available and /etc/apache2/sites-enabled

==libapache2-mod-php5==

If you plan on using PHP with Apache, install this package.

==mysql-server==

Before making any changes, be sure to stop the MySQL daemon.

sudo stop mysql

If you wish to change the default data directory from /var/lib/mysql to /srv or /srv/mysql you will have to edit /etc/mysql/my.cnf

datadir=/srv/mysql

You may also wish to change the bind address if you want to access the server remotely

bind-address = 192.168.1.3

As noted in the my.cnf file, you have to adjust /etc/apparmor.d/usr.sbin.mysql to allow apparmor to allow mysql into the alternate directory.

/srv/mysql r,
/srv/mysql/** rwk,

==php5-mysql==

If you plan on accessing a MySQL database with PHP, install this package.

=Login Server=

==nis==

After installation, NIS will not start up properly.

Edit <tt>/etc/default/nis</tt>

NISSERVER=master
NISCLIENT=false

Edit <tt>/etc/yp.conf</tt> so that the NIS server can find itself faster. Left blank, YP will auto-search for servers.

ypserver 127.0.0.1

Edit <tt>/etc/ypserv.securenets</tt>

255.255.255.0 192.168.1.0<

Now run the following commands

sudo /usr/lib/yp/ypinit -m
sudo /etc/init.d/nis restart

=Media Server=

==minidlna==

Installing A Server - Revision history

BrainwreckedTech: /* Networking */ Removed Network Interfaces Switching Names -- Network names are now en[x]p[y] in GNU/Linux. Changed reference from netcfg to netctl for Arch.

BrainwreckedTech: 1 revision