Re: ipfwadm error msg

From: S. Faruque Ahmed <>
Date: Fri, 22 May 1998 07:24:01 +0600

In linux you will have to compile a new kernel to possess certain
capabilities that are needed with ipfwadm, especially when you want to
apply transparent proxying. I'm not sure about your error message, but it
seems that something might be missing with your kernels tcp/ip capability.

Look into the instructions on how to build a new kernel; in Slackware it
will be in /usr/src/linux => README.
Basically, you will have to turn on necessary capabilities like TCP/IP
Networking, etc. But for transparent proxy to work you will have to
compile it in EXPERIMENTAL mode (I lost a few days myself not knowing this
and trying to edit the config file manually, someone has got to put this in
the FAQ). Thats probably the first option you will see while doing the
configure script. This option will lead to further new options that will
allow you, among other things, to choose IP_TRANSPARENT_PROXY, which will
be a must in the ipfwadm rules you'll use later . Read the help facility
while making the configure script, it really is helpful .

With the new kernel all the ipfwadm rules should work smoothly. Good luck!

Before finishing I'd like to take this opportunity to thank all the people
who helped me out in my last question to this list!


At 04:42 PM 5/21/98 -0500, you wrote:
>I'm new at linux, so this may be a stupid question - but why do I get the
>following error:
>ipfwadm: setsockopt failed: Protocol not available,
>when I run this command line:
>ipfwadm -I -a accept -P tcp -D 0/0 80 -r 3128
>I'm running ipfwadm 2.3.0
>Squid is setup to listen on port 3128.
>Is it something to do with my TCP Wrapper?
>I've got my cisco router redirecting port 80 traffic great. I'm just
>missing something with the ipfwadm.
>Thanks in advance for any help.
>Joslyn Main, MCSE CNE
>Westman Communications
>Brandon, MB
Received on Thu May 21 1998 - 18:19:21 MDT

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