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Re: Debian 11: How to disable IPv6



On 7/12/22 10:21, Lee wrote:
On 7/11/22, rhkramer  wrote:
 From the peanut gallery: I disabled IPv6 quite some time ago.  I don't
recall how I did it, but I might have that information in my notes, somewhere.

The reason that I disabled it (which might not be totally logical) is that
in IPv4, I have always had my computers (and LAN) behind a NAT device.
A NAT device does not necessarily act like a stateful firewall.

Years ago I ran a TOR middle node ... and noticed someone scanning my
internal network!!  Turns out they were using loose source routing to
get around NAT:
   https://en.wikipedia.org/wiki/Loose_Source_Routing
     Loose Source Routing is an IP option which can be used for address
translation.

My cable modem was quite willing to forward packets addressed to the
publicly addressable outside IP address of the box to my internal LAN
with the RFC-1918 address space .. that I thought was unreachable from
the public Internet because NAT :(

So lesson learned - get a firewall or router that will drop packets
that have IP options set.

Regards,
Lee
Your cable modem is NOT a router.

If you want that sort of protection, get a reflashable router and put dd-wrt in it.

Only one person in about18 years has come thru dd-wrt, and I had to give him the credentials on the phone. I would estimate that dd-wrt has blocked a billion
attacks or more in that some time frame. The exceptions are a NAT
that allows me to serve my own web page. No tracking other than the logs apache2
keeps. No commercials, just me blowing my own horn. Boring...

.


Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>


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