[clug] How to prevent port forwarding

[Kim Holburn]

I remember there was a guy who had a method to tell how many hosts  
were behind a firewall.  I just forget the method but I think it  
either was the guy who did all that weird stuff with indirect  
traceroute (using TCP related packets as traceroute)  I just can't  
remember the names of any of it off-hand.

Maybe fft:

http://lists.debian.org/debian-devel/2002/08/msg00404.html

lft:

http://pwhois.org/lft/


On 2006 Apr 22, at 11:09 PM, Christopher Zhang wrote:

> Hi,
>
> I am interested to find out if it is possible, if so, how, that  
> some ISPs prevent 1 registered Internet user to distribute their  
> Internet connection by running their computer as a gateway for  
> other users to route through. The closest thing I can think of is  
> TTL, since if other hosts are routed through the legitimate host,  
> then their TTL will be at least be 1 less than if it were coming  
> from the legitimate host, without any artificial changes. Is this a  
> plausible way for ISPs ? Can anyone show me some iptables commands  
> that the ISPs would do? and also how can I change my TTLs and so on.
>
> Thanks
>
> Chris
> -- 
> linux mailing list
> linux at lists.samba.org
> https://lists.samba.org/mailman/listinfo/linux

-- 
Kim Holburn
Security Manager, National ICT Australia Ltd.
Ph: +61 2 61258620 M: +61 417820641  F: +61 2 6230 6121
mailto:kim.holburn at nicta.com.au  aim://kimholburn
skype://kholburn - PGP Public Key on request
Cacert Root Cert: http://www.cacert.org/cacert.crt
Aust. Spam Act: To stop receiving mail from me: reply and let me know.

Use ISO 8601 dates [YYYY-MM-DD] http://www.saqqara.demon.co.uk/ 
datefmt.htm
Democracy imposed from without is the severest form of tyranny.
                           -- Lloyd Biggle, Jr. Analog, Apr 1961