FAX Gateway - Sendmail/Procmail Configuration

The simplest method available is to create a "fax.your-domain.com" sub domain in your internal DNS to which all outbound faxes are sent so Sendmail can route them to the fax-gw script via Procmail. The creation of the DNS sub domain is outside the scope of this document.

In this configuration, it is assumed that mail in "your-domain.com" is routed via DNS MX records and that your Asterisk server, asterisk.your-domain.com, is not on the same host as your mail gateway.

Sendmail Gateway

On the mail gateway, edit the following file to contain:

• /etc/mail/mailtertable

  fax.your-domain.com smtp:[asterisk.your-domain.com]
  

Sendmail on the Asterisk Server

On the Asterisk server, edit the following files to contain:

• /etc/mail/sendmail.mc

  LOCAL_DOMAIN(`fax.your-domain.com')dnl
  

• /etc/mail/sendmail.cf

  C{w}fax.your-domain.com
  

• /etc/mail/virtusertable

  @fax.your-domain.com asterisk
  

Procmail on the Asterisk Server

On the Asterisk server, edit the .procmailrc file of the asterisk user in the proper home directory.

• ~asterisk/.procmailrc

  LOGFILE=$HOME/procmail.log
  FORMAIL = "/usr/bin/formail"
  #VERBOSE=on
  LOG="Logging ${LOGFILE} for ${LOGNAME}, "
  
  # This recipe will deliver faxes only if the sender has
  # authenticated through mail gateway for SMTP
  # or sent via our webmail
  
  ####
  
  :0
  * ^Received: from .*\(authenticated bits=0\) .*by mailserver\.your-domain\.com
  
  {
          :0
          {
  
  #Get the full To: address
           :0
           * ^To:[         ]*\/[^  ].*        {
                   TO_=$MATCH
           }
  
  }
  
           :0
           *
           {
  # Get the username portion of the To: address (Fax number to send to)
  RECIP_FAX_NUM=`echo "${TO_}" | awk -F@ '{ print $1 }'`
           }
  
           :0
           *        {
  # Get the sender's address, ignore Reply-To:
  SENDER_MAIL=`formail -I"Reply-To:" -rt -xTo: | expand | sed -e 's/^[ ]*//g' -e 's/[ ]*$//g'`
                    }
  
  # Send the message to the AGI for fax processing
  :0
  *
  | /usr/share/asterisk/agi-bin/fax-gw/fax-gw.agi -s $SENDER_MAIL -t $RECIP_FAX_NUM
  }
  
  ###########
  
  # Mail sent to *@fax.your-domain.com from unauthenticated users gets thrown out
  # Sends a message back saying it must be authenticated.
  :0 c
  * ! ^Received: from .*\(authenticated bits=0\) .*by mailserver\.your-domain\.com
  #/dev/null
  
                   | (formail -rI"Precedence: junk" \
                        -A"X-Loop: [EMAIL PROTECTED]" ; \
                      echo "Your email was received by the Asterisk Fax Gateway."; \
                      echo ""; \
                      echo "However, you did not send your message through the authenticated mail SMTP server - so your fax will NOT be sent."; \
                      echo ""; \
                      echo "Please consult XXXX@your-domain.com for help"; \
                     ) | $SENDMAIL -oi -t -fpostmaster@your-domain.com
  
  :0
  *
  /dev/null