Proxy server

Better late than never, this post has sat in draft for a nearly three months. I had a laptop running Ubuntu acting as a proxy server to filter all the kids’ internet traffic and decided back in February that it was getting a bit long in the tooth. It was a Compaq M700 laptop, with a 400MHz processor, 384MB RAM and an 8GB hard disc. A long time since it had been state of the art! The last straw came when I couldn’t upgrade the operating system to the latest version as I didn’t have enough disc space. The old laptop provided several functions for me, so these would have to migrated to the replacement machine.

A few days later, I bought a Dell D610 laptop (Celeron 2.0GHz, 40GB hard disc) off Ebay and some additional memory to take it to 2GB.

I had downloaded Ubuntu Server 10.10 about the same time and burnt the ISO to CD, however when I came to use it I found the image was incomplete, so had to download it again. Second time lucky.

The notes below are for me as an aid for future rebuilds, but may help someone else with their configuration.

I installed the operating system using pretty much the default settings and after it had finished installing and restarted, I changed the network settings to use a static IP address instead of DHCP.

sudo vi /etc/network/interfaces

I changed the primary interface from:

auto eth0
iface eth0 inet dhcp


auto eth0
iface eth0 inet static
address 10.x.x.100
network 10.x.x.0
broadcast 10.x.x.255
gateway 10.x.x.x

Or at least my specific details instead of those above.

I was going to edit the the DNS settings

sudo vi /etc/resolv.conf

but they had already correctly got my DNS settings, so I didn’t need to change the nameserver entry.

I then restarted the networking

sudo /etc/init.d/networking restart

OK, now the fun begins!

The old laptop provides the following:

  • Webserver – Apache, PHP
  • Filter proxy server – Squid, Dansguardian
  • Email spam filtering – SpamAssassin

It was all managed using Webmin, and I also had VNC configured to give me a session onto the display, yes I know its a server, but I installed a GUI to make my life easier.

First I installed webmin to make my life easier:

sudo aptitude install perl libnet-ssleay-perl openssl libauthen-pam-perl libpam-runtime libio-pty-perl libmd5-perl apt-show-versions


sudo dpkg -i webmin_1.530_all.deb

Once Webmin was installed it simplified the installation of other requirements. NTP to ensure that the time was synchronised with the rest of my network.

install ntp
cd /etc
sudo vi ntp.conf
remove server replace with sarig.midkemia.local (my domain controller and time source).

Next to join it to my domain; install following packages:

sudo vi krb5.conf

default_realm = MIDKEMIA.LOCAL
dns_lookup_realm = false
dns_lookup_kdc = false
ticket_lifetime = 24h
# The following krb5.conf variables are only for MIT Kerberos.
krb4_config = /etc/krb.conf
krb4_realms = /etc/krb.realms
kdc_timesync = 1
ccache_type = 4
forwardable = true
proxiable = true

default = FILE:/var/log/krb5libs.log
kdc = FILE:/var/log/krb5kdc.log
admin_server = FILE:/var/log/kadmind.log

# The following encryption type specification will be used by MIT Kerberos
# if uncommented.  In general, the defaults in the MIT Kerberos code are
# correct and overriding these specifications only serves to disable new
# encryption types as they are added, creating interoperability problems.

#    default_tgs_enctypes = aes256-cts arcfour-hmac-md5 des3-hmac-sha1 des-cbc-crc des-cbc-md5
#    default_tkt_enctypes = aes256-cts arcfour-hmac-md5 des3-hmac-sha1 des-cbc-crc des-cbc-md5
#    permitted_enctypes = aes256-cts arcfour-hmac-md5 des3-hmac-sha1 des-cbc-crc des-cbc-md5

# The following libdefaults parameters are only for Heimdal Kerberos.
v4_instance_resolve = false
v4_name_convert = {
host = {
rcmd = host
ftp = ftp
plain = {
something = something-else
fcc-mit-ticketflags = true

kdc = sarig
admin_server = sarig.midkemia.local
default_domain = midkemia.local
kdc =
kdc =
kdc =
admin_server =
default_domain =
kdc =
admin_server =
kdc =
kdc =
admin_server =
kdc =
kdc =
admin_server =
kdc =
kdc =
admin_server =
default_domain =
krb524_server =
kdc =
admin_server =
kdc =
kdc =
kdc =
admin_server =
1TS.ORG = {
kdc =
admin_server =
kdc =
admin_server =
kdc =
admin_server =
kdc =
kdc =
kdc =
kdc =
admin_server =
default_domain =
kdc =
kdc =
admin_server =
kdc =
kdc =
admin_server =
} = {
kdc =
kdc =
kdc =
admin_server =
default_domain =

.midkemia.local = MIDKEMIA.LOCAL
midkemia.local = MIDKEMIA.LOCAL

krb4_convert = true
krb4_get_tickets = false

pam = {
debug = false
ticket_lifetime = 36000
renew_lifetime = 36000
forwardable = true
krb4_convert = false

kinit administrator@MIDKEMIA.LOCAL

should prompt for password and not throw error

vi /etc/samba/smb.conf

# Sample configuration file for the Samba suite for Debian GNU/Linux.
# This is the main Samba configuration file. You should read the
# smb.conf(5) manual page in order to understand the options listed
# here. Samba has a huge number of configurable options most of which
# are not shown in this example
# Any line which starts with a ; (semi-colon) or a # (hash)
# is a comment and is ignored. In this example we will use a #
# for commentary and a ; for parts of the config file that you
# may wish to enable
# NOTE: Whenever you modify this file you should run the command
# “testparm” to check that you have not made any basic syntactic
# errors.

#======================= Global Settings =======================

log level = 3
log file = /var/log/samba/log.%m
passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .
winbind enum users = Yes
winbind enum groups = Yes
winbind use default domain = Yes
winbind nested groups = Yes
winbind separator = +
idmap uid = 600-20000
idmap gid = 600-20000
socket options = TCP_NODELAY
obey pam restrictions = yes
client ntlmv2 auth = yes
wins server = 10.x.x.3
client use spnego = yes
map to guest = bad user
winbind trusted domains only = yes
encrypt passwords = true
passdb backend = tdbsam
passwd program = /usr/bin/passwd %u
template shell = /bin/bash
dns proxy = no
preferred master = no
server string = %h server (Samba, Ubuntu)
invalid users = root
unix password sync = yes
template homedir = /home/%D/%U
workgroup = MIDKEMIA0
syslog = 0
security = ADS
panic action = /usr/share/samba/panic-action %d
usershare allow guests = yes
max log size = 1000
pam password change = yes
smb ports = 139

## Browsing/Identification ###

# Change this to the workgroup/NT-domain name your Samba server will part of

# server string is the equivalent of the NT Description field

# Windows Internet Name Serving Support Section:
# WINS Support – Tells the NMBD component of Samba to enable its WINS Server
;   wins support = no

# WINS Server – Tells the NMBD components of Samba to be a WINS Client
# Note: Samba can be either a WINS Server, or a WINS Client, but NOT both

# This will prevent nmbd to search for NetBIOS names through DNS.

# What naming service and in what order should we use to resolve host names
# to IP addresses
;   name resolve order = lmhosts host wins bcast

#### Networking ####

# The specific set of interfaces / networks to bind to
# This can be either the interface name or an IP address/netmask;
# interface names are normally preferred
;   interfaces = eth0

# Only bind to the named interfaces and/or networks; you must use the
# ‘interfaces’ option above to use this.
# It is recommended that you enable this feature if your Samba machine is
# not protected by a firewall or is a firewall itself.  However, this
# option cannot handle dynamic or non-broadcast interfaces correctly.
;   bind interfaces only = true

#### Debugging/Accounting ####

# This tells Samba to use a separate log file for each machine
# that connects

# Cap the size of the individual log files (in KiB).

# If you want Samba to only log through syslog then set the following
# parameter to ‘yes’.
;   syslog only = no

# We want Samba to log a minimum amount of information to syslog. Everything
# should go to /var/log/samba/log.{smbd,nmbd} instead. If you want to log
# through syslog you should set the following parameter to something higher.

# Do something sensible when Samba crashes: mail the admin a backtrace

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

# “security = user” is always a good idea. This will require a Unix account
# in this server for every user accessing the server. See
# /usr/share/doc/samba-doc/htmldocs/Samba3-HOWTO/ServerType.html
# in the samba-doc package for details.

# You may wish to use password encryption.  See the section on
# ‘encrypt passwords’ in the smb.conf(5) manpage before enabling.

# If you are using encrypted passwords, Samba will need to know what
# password database type you are using.

;   guest account = nobody

# This boolean parameter controls whether Samba attempts to sync the Unix
# password with the SMB password when the encrypted SMB password in the
# passdb is changed.

# For Unix password sync to work on a Debian GNU/Linux system, the following
# parameters must be set (thanks to Ian Kahan <<> for
# sending the correct chat script for the passwd program in Debian Sarge).

# This boolean controls whether PAM will be used for password changes
# when requested by an SMB client instead of the program listed in
# ‘passwd program’. The default is ‘no’.

# This option controls how nsuccessful authentication attempts are mapped
# to anonymous connections

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

# Is this machine able to authenticate users. Both PDC and BDC
# must have this setting enabled. If you are the BDC you must
# change the ‘domain master’ setting to no
;   domain logons = yes
# The following setting only takes effect if ‘domain logons’ is set
# It specifies the location of the user’s profile directory
# from the client point of view)
# The following required a [profiles] share to be setup on the
# samba server (see below)
;   logon path = \\%N\profiles\%U
# Another common choice is storing the profile in the user’s home directory
;   logon path = \\%N\%U\profile

# The following setting only takes effect if ‘domain logons’ is set
# It specifies the location of a user’s home directory (from the client
# point of view)
;   logon drive = H:
;   logon home = \\%N\%U

# The following setting only takes effect if ‘domain logons’ is set
# It specifies the script to run during logon. The script must be stored
# in the [netlogon] share
# NOTE: Must be store in ‘DOS’ file format convention
;   logon script = logon.cmd

# This allows Unix users to be created on the domain controller via the SAMR
# RPC pipe.  The example command creates a user account with a disabled Unix
# password; please adapt to your needs
; add user script = /usr/sbin/adduser –quiet –disabled-password –gecos “” %u

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

# If you want to automatically load your printer list rather
# than setting them up individually then you’ll need this
;   load printers = yes

# lpr(ng) printing. You may wish to override the location of the
# printcap file
;   printing = bsd
;   printcap name = /etc/printcap

# CUPS printing.  See also the cupsaddsmb(8) manpage in the
# cupsys-client package.
;   printing = cups
;   printcap name = cups

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

# Using the following line enables you to customise your configuration
# on a per machine basis. The %m gets replaced with the netbios name
# of the machine that is connecting
;   include = /home/samba/etc/smb.conf.%m

# Most people will find that this option gives better performance.
# See smb.conf(5) and /usr/share/doc/samba-doc/htmldocs/Samba3-HOWTO/speed.html
# for details
# You may want to add the following on a Linux system:
#         SO_RCVBUF=8192 SO_SNDBUF=8192

# The following parameter is useful only if you have the linpopup package
# installed. The samba maintainer and the linpopup maintainer are
# working to ease installation and configuration of linpopup and samba.
;   message command = /bin/sh -c ‘/usr/bin/linpopup “%f” “%m” %s; rm %s’ &

# Domain Master specifies Samba to be the Domain Master Browser. If this
# machine will be configured as a BDC (a secondary logon server), you
# must set this to ‘no’; otherwise, the default behavior is recommended.
;   domain master = auto

# Some defaults for winbind (make sure you’re not using the ranges
# for something else.)

# The following was the default behaviour in sarge,
# but samba upstream reverted the default because it might induce
# performance issues in large organizations.
# See Debian bug #368251 for some of the consequences of *not*
# having this setting and smb.conf(5) for details.
#  winbind seperator = +

#Setup usershare options to enable non-root users to share folders
# with the net usershare command.

# Maximum number of usershare. 0 (default) means that usershare is disabled.
;   usershare max shares = 100

# Allow users who’ve been granted usershare privileges to create
# public shares, not just authenticated ones

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

# Un-comment the following (and tweak the other settings below to suit)
# to enable the default home directory shares.  This will share each
# user’s home directory as \\server\username
;   comment = Home Directories
;   browseable = no

# By default, the home directories are exported read-only. Change the
# next parameter to ‘no’ if you want to be able to write to them.
;   read only = yes

# File creation mask is set to 0700 for security reasons. If you want to
# create files with group=rw permissions, set next parameter to 0775.
;   create mask = 0700

# Directory creation mask is set to 0700 for security reasons. If you want to
# create dirs. with group=rw permissions, set next parameter to 0775.
;   directory mask = 0700

# By default, \\server\username shares can be connected to by anyone
# with access to the samba server.  Un-comment the following parameter
# to make sure that only “username” can connect to \\server\username
# This might need tweaking when using external authentication schemes
;   valid users = %S

# Un-comment the following and create the netlogon directory for Domain Logons
# (you need to configure Samba to act as a domain controller too.)
;   comment = Network Logon Service
;   path = /home/samba/netlogon
;   guest ok = yes
;   read only = yes
;   share modes = no

# Un-comment the following and create the profiles directory to store
# users profiles (see the “logon path” option above)
# (you need to configure Samba to act as a domain controller too.)
# The path below should be writable by all users so that their
# profile directory may be created the first time they log on
;   comment = Users profiles
;   path = /home/samba/profiles
;   guest ok = no
;   browseable = no
;   create mask = 0600
;   directory mask = 0700

comment = All Printers
browseable = no
path = /var/spool/samba
printable = yes
guest ok = no
read only = yes
create mask = 0700

# Windows clients look for this share name as a source of downloadable
# printer drivers
comment = Printer Drivers
path = /var/lib/samba/printers
browseable = yes
read only = yes
guest ok = no
# Uncomment to allow remote administration of Windows print drivers.
# Replace ‘ntadmin’ with the name of the group your admin users are
# members of.
;   write list = root, @ntadmin

# A sample share for sharing your CD-ROM with others.
;   comment = Samba server’s CD-ROM
;   read only = yes
;   locking = no
;   path = /cdrom
;   guest ok = yes

# The next two parameters show how to auto-mount a CD-ROM when the
#    cdrom share is accesed. For this to work /etc/fstab must contain
#    an entry like this:
#       /dev/scd0   /cdrom  iso9660 defaults,noauto,ro,user   0 0
# The CD-ROM gets unmounted automatically after the connection to the
# If you don’t want to use auto-mounting/unmounting make sure the CD
#    is mounted on /cdrom
;   preexec = /bin/mount /cdrom
;   postexec = /bin/umount /cdrom

writeable = yes
valid users = MIDKEMIA+ian,@MIDKEMIA+unixadm
browsable = yes
create mode = 777
path = /shared

guest account = ian
writeable = yes
path = /var/www
valid users = MIDKEMIA+administrator,@MIDKEMIA+unixadm
create mode = 777
browsable = yes

guest account = ian
writeable = yes
public = yes
path = /etc/spamassassin/sa-learn


vi /etc/hosts
add 10.x.x.3 sarig.midkemia.local sarig
10.x.x.4 nakor.midkemia.local nakor

vi /etc/nsswitch.conf

# /etc/nsswitch.conf
# Example configuration of GNU Name Service Switch functionality.
# If you have the `glibc-doc-reference’ and `info’ packages installed, try:
# `info libc “Name Service Switch”‘ for information about this file.

passwd: files winbind
shadow: files winbind
group: files winbind

#hosts: db files nisplus nis dns
hosts: files dns wins

# Example – obey only what nisplus tells us…
#services: nisplus [NOTFOUND=return] files
#networks: nisplus [NOTFOUND=return] files
#protocols: nisplus [NOTFOUND=return] files
#rpc: nisplus [NOTFOUND=return] files
#ethers: nisplus [NOTFOUND=return] files
#netmasks: nisplus [NOTFOUND=return] files

bootparams: nisplus [NOTFOUND=return] files

ethers: db files
netmasks: files
networks: files dns
protocols: db files
rpc: files
services: files

netgroup: files

publickey: nisplus

automount: files
aliases: files nisplus

sudo net ads join -U administrator

install files for rlogin rsh-rod-server ssh

Next set up Apache webserver. Change www permissions and copy internal, external and squid-reports from old server to www
Configure appropriate virtual servers

Next install Danguardian filtering.
This requires squid proxy server installed.
In webmin choose Squid Proxy Server in Un-Used Modules, it told me it was not installed and offered to download and install it for me. Sounds good and just worked.

Configuration, Access Control,
Access Control Lists
Create new ACL Client Address called lan, from IP 10.x.x.0 netmask 24
Create new ACL Client Address called our_networks, from IP 10.x.x.0 netmask 24
Proxy restrictions
Add proxy restriction Allow our_networks and move above Allow localhost

Authentication Programs
Number of authentication programs 5
Authentication cache time 2 hours
Authentication realm Squid proxy-caching web server

Install squid-cgi package

Download Dansguardian Webmin module
Install Dansguardian package, this installs to a different location than the Webmin module expects, so edit module config:
Full path to DG binary   /usr/sbin/dansguardian
Command to restart DG (if allowed)  /usr/sbin/dansguardian -r
Command to start DG (if allowed)  /usr/sbin/dansguardian
Command to stop DG (if allowed)  pkill dansguardian

Hmm that’s it then. That was so much easier than when I first installed it.

Install sarg package
Edit webmin module config for sarg
Full path to SARG configuration file  /etc/sarg/sarg.conf

Install mailutils package

Finally install and configure SpamAssassin. I used the existing as a guideline.

The laptop ran fine for a few hours and then crashed. Hmm, that’s not a good start. On investigating it was very hot. After letting it all cool down, it worked again, so my thoughts were a ventilation problem. Then it re-occured, OK, there’s something else going on!
It turns out the cooling fan isn’t running, so that was why it overheated. Google turned up dellfand, which I downloaded and made following the site instructions. I set the fan low speed to 35C and fan high to 40C and set it to start on system start.

Update: This worked fine until the hot weather last week, when it overheated again. I have now changed the fan low to 30C and fan high to 35C and the system now is fairly stable at about 35C most of the time.

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