[ale] Strange happenings since I upgraded to 2.2 kernel

[masmith at bsat.com (Michael A. Smith)]

> -----Original Message-----
> From: kaboom at dobzhansky.angband.org
> [mailto:kaboom at dobzhansky.angband.org]On Behalf Of Chris Ricker
> Sent: Sunday, April 25, 1999 6:58 PM
> To: Michael A. Smith
> Subject: Re: [ale] Strange happenings since I upgraded to 2.2 kernel
>
>
> On Mon, 19 Apr 1999, Michael A. Smith wrote:
>
> >     I was wondering if anyone has been playing around with the 2.2
> > kernel(using slackware 4.0 or Redhat's Starbuck) and
> noticed anything
> > strange with incoming tcpip.  To be more specific, I have a
> machine that
> > dual boots NT(I don't boot it that often) and Linux 2.2.5.
> I can ping and
> > ftp to my NT machine from work but I can't ping or ftp to
> my linux machine
> > whenever it's booted.  I thought for a while that I was
> having problems with
> > the cable company(I have a cable modem) but I have had them
> research it and
> > they say that no outages exist in my area whenever I'm
> having problems.
> >
> >     I have come to the conclusion that I have set up Linux
> incorrectly or
> > something new is turned on by default in the new kernel
> that wasn't on by
> > default in Kernel 2.0.36(Redhat 5.2).  The only thing that
> I have changed
> > from the releases is the required changes to use ipchains
> instead of ipfwadm
> > for ip masquerading.  Anyone know if ipchains or anything
> in the Kernel
> > would make my machine un-pingable or un-traceroutable.  I
> don't have any
> > problems when I'm at home with an outbound connection and I
> have a static IP
> > so it's not a DHCP issue.
> >
>
> Linux 2.2 now adds default routes for you.  Your network
> scripts might not
> take that into account, and you could be screwing up your
> routing tables.
>
> Other than that, it's almost definitely not a kernel issue.
> Perhaps you've
> got ipchains misconfigured (you're not blocking all ICMP /
> UDP packets, are
> you)?
>
> later,
> chris
>
> --
> Chris Ricker
> kaboom at gatech.edu
>
> chris.ricker at m.cc.utah.edu
>
>

I actually found the problem after looking at the README

Here is the fix:

''''
6.1 Masquerading/forwarding doesn't work!
Make sure that packet forwarding is enabled (in recent kernels it is
disabled by default, meaning that packets never even try to traverse the
`forward' chain). You can override this (as root) by typing


# echo 1 > /proc/sys/net/ipv4/ip_forward
#


If this works for you, you can put this somewhere in your bootup scripts so
it is enabled every time; you'll want to set up your firewalling before this
command runs though, otherwise there's an opportunity for packets to slip
through.
''''


Thanks for replying.....