Re: basic firewall question

["Jeffrey L. Taylor" <jeff@austinblues.dyndns.org>]

Quoting Roberto Sanchez <sanchezr@hotmail.com>:
> 
> I am planning on getting DSL in the near future, so I have been considering 
> what to do about a firewall.
> 
> My intended setup is like this:
> 
> www -> DSL modem -> cable/DSL router w/ hardware FW -> small LAN
> 
> However, I would still like to have a firewall on each individual machine.  
> I downloaded firestarter on one machine and played around with it some.  
> But I'm not sure if that is the best tool.  I basically want to block all 
> incoming traffic except for SSH and DHCP (so I can get an IP address from 
> the router).  This setup seemed pretty easy with the little wizard that is 
> included.  I also need to be able to print across my local network.
> 
> I tried out several services (telnet, ftp, and http) and it blocked those 
> requests, but I am not sure how indicative that is of the security level.  
> I also tried ssh and that worked fine.
> 

On the LAN, try nmap and Nessus.  From the Internet, www.grc.com and
www.vulnerabilities.org.  The former is the Web site for Steve Gibson,
a controversial figure.  His Shields Up! scan is Window-centric, but a
decent starting point.  The latter URL is basically a Nessus scan.
It's good, but may point vulnerabilities that you do not have.  E.g.,
it sometimes assumes which daemon you are running on a given port.  It
flagged a Sendmail vulnerability.  I have run several different MTAs
on port 25, but never Sendmail.

HTH,
  Jeffrey