<HTML ><HEAD ><TITLE >Network security</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><LINK REL="HOME" TITLE="Linux PPP HOWTO" HREF="index.html"><LINK REL="UP" TITLE="Linking two networks using PPP" HREF="wan.html"><LINK REL="PREVIOUS" TITLE="Setting up the routing" HREF="x1410.html"><LINK REL="NEXT" TITLE="After the link comes up - the /etc/ppp/ip-up script" HREF="ip-up.html"></HEAD ><BODY CLASS="SECT1" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" ><A HREF="http://www.linuxports.com/howto/ppp" TARGET="_top" >Linux PPP HOWTO</A ></TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="x1410.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Chapter 24. Linking two networks using PPP</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="ip-up.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="AEN1418">24.3. Network security</H1 ><P >If you are linking you LAN to the Internet using PPP - or even just to a "foreign" LAN, you need to think about security issues. I strongly urge you to think about setting up a firewall!</P ><P >You should also speak to the LAN administrator at your site <EM >BEFORE</EM > you start linking to foreign LANs or the Internet this way. Failure to do so could earn you anything from no reaction to really serious trouble!</P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="x1410.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="ip-up.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Setting up the routing</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="wan.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >After the link comes up - the <TT CLASS="LITERAL" >/etc/ppp/ip-up</TT > script</TD ></TR ></TABLE ></DIV ></BODY ></HTML >