Re: Port 21, 23, and 80 are open according to Shields Up at grc.com

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Hi.

> On Sat, 2004-09-11 at 19:09, Mike wrote:
> > Hi Group:
> > 
> > I've tested for open ports from all the LAN clients behind my linux
> > box router/gateway/firewall and all of them come up with the same
> > results: port 21, 23, and 80 are open according to the results of the
> > Steve Gibson Shields Up test.
> > 
> > I can't figure out how this can be happening.
> > I've run a full nmap -P0 (that's a zero) on all my local ip addresses
> > - 192.168.169.*
> 
> you need to keep in mind that if your netfilter box is performing
> MASQ/SNAT for your LAN machines--the IP being scanned by grc.com is the
> public IP of the netfilter box.
> 
> unless your doing some DNATs to machines on your LAN--you should focus
> your efforts on the netfilter machine itself.
> 
> "netstat -lntu" would be a good place to start.
> 
> i've always questioned the output of web-based scanners like grc.com;
> however, i just went to grc.com and tried it out, and achieved a
> *perfect* "TruStealth" rating...which must mean i'm super l33t like
> stevie...  :-P

For whatever it may be worth:  I have linux 2.6.0 running on my firewall
machine, and 2.6.9-rc1 running on a machine behind it, and I get (and
have always gotten) a *perfect* TruStealth result relative to both
machines.

jbh


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