Some questions about IP Masquerading

[Mark Phillips <mark@ist.flinders.edu.au>]

I am currently trying to install IP masquerading at home.  I've been
reading the Mini IP Masquerading HOWTO, and I have some questions
which I am hoping someone can answer.


1. The HOWTO says to add the following lines to /etc/rc.d/rc.local:

  /sbin/depmod -a
  /sbin/modprobe ip_masq_ftp
  /sbin/modprobe ip_masq_raudio
  ...etc

I presume that under debian I actually just add these modules to
/etc/modules??


2. In my /lib/modules/2.0.36/ipv4 directory I have the following modules:

ip_masq_cuseeme.o  ip_masq_irc.o      ip_masq_raudio.o
ip_masq_ftp.o      ip_masq_quake.o    ip_masq_vdolive.o

>From this I am guessing that by installing these modules, I will be able
to run ftp, irc, quake and real audio applications.  I am guessing vdolive
is short for "video live"??  And I have no idea about "cuseeme"??

Why isn't "http" here --- doesn't it need a module?  What about
"rlogin", "telnet", "ping" and "pop3" (email)??


3.  What does "ipv4" stand for?  Is it specifically masquerading stuff?


4.  The HOWTO says:

  IMPORTANT: IP forwarding is disabled by default since 2.0.34
  kernels, please make sure you enable it by running
         echo "1" > /proc/sys/net/ipv4/ip_forward 

This seems a very strange way to enable something.  Does it need to be
done at boot time, or when?  Why is it done like this?


5.  I'm a little bit hazy about what "ipfwadm" does and how it does
it.  I imagine as I read further I'll find out, but any enlightening
summaries would be appreciated.

Thanks,

Mark.



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