242 lines
3.9 KiB
HTML
242 lines
3.9 KiB
HTML
<HTML
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><HEAD
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><TITLE
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>After the link comes up - the /etc/ppp/ip-up script</TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.52"><LINK
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REL="HOME"
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TITLE="Linux PPP HOWTO"
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HREF="index.html"><LINK
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REL="PREVIOUS"
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TITLE="Network security"
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HREF="x1418.html"><LINK
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REL="NEXT"
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TITLE="Handling email queues"
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HREF="x1448.html"></HEAD
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><BODY
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CLASS="CHAPTER"
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BGCOLOR="#FFFFFF"
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TEXT="#000000"
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LINK="#0000FF"
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VLINK="#840084"
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ALINK="#0000FF"
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><DIV
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CLASS="NAVHEADER"
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><TABLE
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><TR
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><TH
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COLSPAN="3"
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ALIGN="center"
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><A
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HREF="http://www.linuxports.com/howto/ppp"
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TARGET="_top"
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>Linux PPP HOWTO</A
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></TH
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></TR
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><TR
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><TD
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WIDTH="10%"
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ALIGN="left"
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VALIGN="bottom"
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><A
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HREF="x1418.html"
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>Prev</A
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></TD
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WIDTH="80%"
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ALIGN="center"
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VALIGN="bottom"
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></TD
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><TD
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WIDTH="10%"
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ALIGN="right"
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VALIGN="bottom"
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><A
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HREF="x1448.html"
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>Next</A
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></TD
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></TR
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></TABLE
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><HR
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ALIGN="LEFT"
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WIDTH="100%"></DIV
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><DIV
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CLASS="CHAPTER"
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><H1
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><A
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NAME="IP-UP"
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>Chapter 25. After the link comes up - the <TT
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CLASS="LITERAL"
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>/etc/ppp/ip-up</TT
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> script</A
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></H1
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><DIV
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CLASS="TOC"
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><DL
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><DT
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><B
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>Table of Contents</B
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></DT
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><DT
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>25.1. <A
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HREF="ip-up.html#AEN1442"
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>Special routing</A
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></DT
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><DT
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>25.2. <A
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HREF="x1448.html"
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>Handling email queues</A
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></DT
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><DT
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>25.3. <A
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HREF="x1455.html"
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>A sample <TT
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CLASS="LITERAL"
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>/etc/ppp/ip-up</TT
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> script</A
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></DT
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><DT
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>25.4. <A
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HREF="x1464.html"
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>Handling email</A
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></DT
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></DL
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></DIV
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><P
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>Once the PPP link is established, pppd looks for
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<TT
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CLASS="LITERAL"
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>/etc/ppp/ip-up</TT
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>. If this script exists and is executable, the
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PPP daemon executes the script. This allows you to automate any special
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routing commands that may be necessary and any other actions that you
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want to occur every time the PPP link is activated.</P
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><P
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>This is just a shell script and can do anything that a shell script can
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do (i.e. virtually anything you want).</P
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><P
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>For example, you can get sendmail to dispatch any waiting outbound
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messages in the mail queue.</P
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><P
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>Similarly, you can insert the commands into ip-up to collect (using pop)
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any email waiting for you at your ISP.</P
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><P
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>There are restrictions on <TT
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CLASS="LITERAL"
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>/etc/ppp/ip-up</TT
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>:-</P
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><P
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> <P
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></P
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><UL
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><LI
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><P
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>It runs in a deliberately restricted environment to enhance
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security. This means you must give a full path to binaries etc.</P
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></LI
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><LI
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><P
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>Technically, <TT
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CLASS="LITERAL"
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>/etc/ppp/ip-up</TT
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> is a <I
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CLASS="EMPHASIS"
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>program</I
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> not a
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script. This means it can be directly executed - and hence it requires
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the standard file magic (<TT
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CLASS="LITERAL"
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>#!/bin/bash</TT
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>) at the start of the first line and must be
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readable and executable by root.</P
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></LI
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></UL
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> </P
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><DIV
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CLASS="SECT1"
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><H1
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CLASS="SECT1"
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><A
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NAME="AEN1442"
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>25.1. Special routing</A
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></H1
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><P
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>If you are linking two LANs, you will need to set up specific routes
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to the 'foreign' LANs. This is easily done using the <TT
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CLASS="LITERAL"
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>/etc/ppp/ip-up</TT
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>
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script. The only difficulty arises if your machine handles multiple PPP
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links.</P
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><P
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>This is because the <TT
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CLASS="LITERAL"
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>/etc/ppp/ip-up</TT
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> is executed for EVERY ppp
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connection that comes up, so you need to carefully execute the correct
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routing commands for the particular link that comes up - and not when
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any other link comes up!</P
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></DIV
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></DIV
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><DIV
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CLASS="NAVFOOTER"
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><HR
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ALIGN="LEFT"
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WIDTH="100%"><TABLE
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WIDTH="100%"
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BORDER="0"
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CELLPADDING="0"
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CELLSPACING="0"
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><TR
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><TD
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WIDTH="33%"
|
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ALIGN="left"
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VALIGN="top"
|
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><A
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HREF="x1418.html"
|
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>Prev</A
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></TD
|
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><TD
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WIDTH="34%"
|
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ALIGN="center"
|
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VALIGN="top"
|
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><A
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HREF="index.html"
|
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>Home</A
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></TD
|
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><TD
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WIDTH="33%"
|
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ALIGN="right"
|
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VALIGN="top"
|
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><A
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HREF="x1448.html"
|
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>Next</A
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></TD
|
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></TR
|
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><TR
|
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><TD
|
|
WIDTH="33%"
|
|
ALIGN="left"
|
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VALIGN="top"
|
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>Network security</TD
|
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><TD
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WIDTH="34%"
|
|
ALIGN="center"
|
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VALIGN="top"
|
|
> </TD
|
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><TD
|
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WIDTH="33%"
|
|
ALIGN="right"
|
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VALIGN="top"
|
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>Handling email queues</TD
|
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></TR
|
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></TABLE
|
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></DIV
|
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></BODY
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></HTML
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> |