Provided by: p3scan_2.1-2_i386 bug


       This is a fully transparent proxy-server for POP3-Clients. It runs on a
       Linux box with iptables (for port re-direction).  It  can  be  used  to
       provide  POP3 email scanning from the internet, to any internal network
       and is ideal for helping to protect your  "Other  OS"  LAN  from  harm,
       especially  when  used  synergically with a firewall and other Internet
       Proxy servers.

       It is designed to  enable  scanning  of  incoming  email  messages  for
       Viruses,  Worms, Trojans, Spam (read as "Un-solicited Bulk Email"), and
       harmfull attachments.  Because viewing HTML mail can enable a "Spammer"
       to  validate  an  email  address  (via  web  bugs), it can also provide
       dangerous HTML tag stripping.


       It works typically in situations where the linux box lies  between  the
       network  you wish to protect and the "outer world".  You have to set up
       a  port  redirection  rule  with  iptables  (see  "IP-Tables   /   Port
       redirecting")  so  that all connections from e.g. inside your office to
       any POP3 server outside in the world will not leave  your  router,  but
       come  to  a  local  port, on which P3Scan listens.  P3Scan receives the
       original destination address of the "outer world" POP3 server from  the
       Linux kernel and connects to that address.

       Anything  received from the client will be sent to the server, and vice
       versa but with a little enhancement: when a message is  sent  from  the
       server  it’s  parsed,  stored  into  a file, and scanned. If a virus is
       found a virus notification is sent instead  of  the  original  infected
       message,  which  can be quarantined or optionally deleted.  The message
       can also be scanned for spam, have  potentially  dangerous  attachments
       renamed, and have potentially malicious HTML parts stripped.

       It   should   be   possible   to   use  any  virus  scanner  using  the
       scannertype=basic configuration option.

       Also, P3Scan provides scannertype=avpd for  high-speed  scanning  using
       for other scan-daemons (trophie, sophie, antivir, ...).

       Neither  the  client  nor the server has to be configured. None of them
       will ever notice that there’s a mail scanner. From the server point  of
       view  the  incoming  connections  are  from  the linux box IP. From the
       client point of wiew the only evidence of the presence  of  p3scan  are
       virus notifications and some additional X-headers.


       iptables - Normally installed by default on major Linux Distributions.
       libpcre - Normally installed by default on major Linux Distributions.
       An Anti-Virus program
         P3Scan is known to work with:
           Kaspersky Anti-Virus for Linux (AVPD)
           Trophie Anti-Virus Daemon
           FRISK F-Prot Antivirus
           Clam Anti-Virus
           Any other virus scanner that can output it’s report to the console
           (stdout) so that it can be captured with "2>&1".
       DSPAM 3.x (optional) -
       Mail::SpamAssassin (optional) -
       renattach (optional) -
       p3pmail (optional) -


       The  following  kernel-parameters  have  to be enabled to get P3Scan to
       work.  If you have no clue about kernel-compiling, then  here  is  some
       good  news:  Most of Linux Distributions (with kernel 2.4.x or greater)
       support what we need by default. However, if your distribution does not
       have it, please read your system documentation on how to add it to your



       Change to the directory where you untar’ed the  program  and  make  any
       system  specific  changes  as  need  to  the "user options" area of the
       Makefile, then, as user: $ make and as root (su root) # make install

       The only binary will be copied to /usr/sbin/p3scan.

       Make install will also copy p3scan.conf and  the  p3scan-xx.mail  files
       into    /etc/p3scan    while    creating    directories    /etc/p3scan,
       /var/run/p3scan,  /var/spool/p3scan,  /var/spool/p3scan/children,   and
       /var/spool/p3scan/notify.   It  will  also  create  a  symbolic link of
       /etc/p3scan/p3scan.mail to the language file specified in the Makefile.

       After  this,  you  must  prepare  your  configuration file as described

       Preparing / Manual Configuration:

       If you decide not to use "make install" (for example,  you  don’t  want
       gcc  on  your  firewall  machine  where p3scan is going to run). Please
       ensure the following directories are created and that  they  are  owned
       and readable/writable by only the user "mail" (default).

       As  root, create the following directories: # mkdir /etc/p3scan # mkdir
       /var/run/p3scan  #  mkdir  -p  /var/spool/p3scan/children  #  mkdir  -p

       Make  them  "owned"  by  the  user  "mail" (default): # chown mail.mail
       /etc/p3scan # chown mail.mail  /var/run/p3scan  #  chown  -R  mail.mail

       Then  make  them read/write by only our user: # chmod 700 /etc/p3scan #
       chmod 700 /var/run/p3scan # chmod -R 700 /var/spool/p3scan

       If you don’t have the user "mail" and do not know how  to  create  this
       user,  please see your operating systems documentation on how to create
       a user.

       Change the symlink /etc/p3scan/p3scan.mail if you wish (this points  to
       the  template which is sent instead of a virus). If you use any special
       character (like German-umlauts äöü) don’t forget to set the charset  to
       "utf8"  (charset="utf8"  vice  charset="iso-8859-1").  Also, ensure the
       leading dot at the end of the file is there and has a  carriage  return
       after the dot.


       The configuration file defaults to /etc/p3scan/p3scan.conf

       This file is a mixture of configuration data and documentation and MUST
       be modified to work  correctly  upon  initial  installation.  You  must
       specify AT LEAST how to call your anti-virus program and how to extract
       the virus name (if one is found).

       The purpose of p3scan is to provide virus  protection  to  an  internal
       network.   So,  not having a virus scanner is not an option. That being
       said, if you still do not want a virus scanner enabled,  you  can  just
       set the scannertype/scanner to basic/"/usr/bin/cat".

       Currently, the default configuration is as follows (see p3scan.conf for
       more info):

          The PID file is stored in: pidfile = /var/run/p3scan/
          The maximum simultaneous scans is: maxchilds = 10
          We listen to any address: ip =
          We listen only on: port = 8110
          targetip and targetport are disabled.
          We run as: user = mail
          We create notification mails in: notifydir = /var/spool/p3scan/notify
             before sending.
          We default to storing infected messages in: virusdir = /var/spool/p3scan
          We keep infected mail.
             "justdelete" is not set.
          We do not check remaining disk space before scanning mail.
             "bytesfree" is not set
          We DO NOT have an Anti-Virus program selected, scanner return code, nor
             regular expression on how to extract a virus name.
             "scanner" is not set
             "viruscode" is not set
             "virusregexp" is not set
          We DO NOT have any "Good" return codes set other than "0" (zero).
             "goodcode" is not set
          We DO NOT demime the message or separate attachments from the original mail
             before scanning.
             "demime" is not set
          We DO NOT send entire lines of email header while processing to keep the
             email client "alive". We send characters instead.
             "broken" is not set.
          We DO NOT check for email marked as "Spam" by your ISP.
             "ispspam" is not set.
          We DO NOT check for "Spam".
             "checkspam/spamcheck" is not set
          We DO NOT rename attachments.
             "renattach" is not pointing to any external program.
          We DO NOT parse HTML code.
             "overwrite" is not set.
          We DO NOT have debug messages being displayed.
             *"debug" is not set.
             * Note: The recommended debug procedure is to call p3scan as such:
                p3scan -d > debug 2>&1
                You can then keep track of the debug messages on another terminal
               with: tail -n 50 -f debug
          We report all program steps to syslog less debug info.
             "quiet" is not set.
          The Virus Report template defaults to /etc/p3scan/p3scan.mail which is
             a symlink to /etc/p3scan/p3scan-xx.mail generated during "make install",
             where xx equals the LANG option set in the Makefile.
          We generate the Virus Report Subject line as:
            "[Virus] found in a mail to you:" <virus name>
            you can change this with the "subject" line in p3scan.conf.
          We generate the Virus Report file disposition line (when justdelete is set):
          notify = Per instruction, the message has been deleted.
       IP-Tables / Port redirecting:

          A rule like:
          iptables -t nat -A PREROUTING -p tcp -i eth0 --dport pop3 -j REDIRECT --to 8110
          is enough. Change eth0 to your device for the inbound connections (your
          office or home network).

          Also, "pop3" must be defined in your "services" file. Normally /etc/services
          If it is not defined, enter the definition you have for 110/tcp. IE: pop-3

          This rule redirects pop3 connections to a local port (like a pop3 server).

       Spam Checking

          The spam checking capability of p3scan has only been tested using
          DSPAM >= 3.0.0-rc2 and Mail::SpamAssassin v2.6-v3.0.1

          If using dspam, you need to install the program according to the
          documentation found at

          The recommended procedure is the virtual-users interface of the mysql

          If you will be scanning for spam using SpamAssassin, you need to install the
          program according to the documentation found at

          The easiest (as fastest) interface to Mail::SpamAssassin is through it’s
          daemon program "spamd" using "spamc".

          You can start spamd as follows before running p3scan:
          *Note: This example is for using SpamAssassin w/mysql
          /usr/bin/spamd -d -u spamd -x -q &


          Is used to rename attachments and is totally configurable.

          Renattach must be compiled, installed, and configured before enabling this
          feature. See the renattach documentation INSTALL and README for further

       HTML Parsing:

          The HTML parsing option is now an external program to p3scan. This
          facilitates using any program you can find. I have written a separate
          program for this function called p3pmail which can be found on the p3scan
          web site.

          P3PMail will obfuscate the tags "href" and "src" the two most dangerous
          HTML tags (IMHO) for email. Of course, if your using a non-html email
          client, you will not have to worry about "web-bugs".


          Call p3scan without any parameters, it will move into the background.
          You can monitor it’s operation via your systems log file.
          You should also test your installation by sending yourself an eicar test
          virus (which will not damage your system). You can get versions of this
          file at

          If you think too much information is being sent to your system logs, you
          can enable the "quiet" option. This will inhibit "normal" messages.

          If P3Scan is started by root, it will change it’s user to "mail" (default)
          after it finishes it’s initial startup.

          If you are using Mail::SpamAssassin, start spamd BEFORE running p3scan.

       RC System / Boot up:

          p3scan comes with two startup scripts, one for FC/RH type systems (init.d),
          and one for Slackware type systems (rc.x). These files will be installed
          depending on your system type. Or, you can add p3scan to your normal default
          startup file. For example, in Slackware place p3scan as follows:

          # echo "/usr/sbin/p3scan" >> /etc/rc.d/rc.local


       p3scan  /etc/p3scan/p3scan.conf  /etc/p3scan/p3scan.mail  dspam   spamd
       spamc renattach


       Please report any bugs to the p3scan support mailing list accessable through:


       Jack S. Lai <laitcg at cox dot net>
       and contributers (see CONTRIBUTERS file).