Re: Port Probing

From: Kris (
Date: 06/07/02

From: "Kris" <>
Date: Fri, 7 Jun 2002 15:11:28 +0200

But I cannot access the ports?...

For example: according to the port scanners, port 25 (smtp) is open.
But when I telnet on port 25, I don't get a reply from my mailserver.

This is normal, because the firewall I have (BlackIce) doesn't have port 25

But why are the scanners *showing* port 25 as an 'open port' ?


"svek" <> schreef in bericht
> "Kris" <> wrote in
> news:3d00ac05$0$6974$
> > Guys, I *am* running Sygate as well! But Sygate only does NAT I
> > believe. I think you can combine it with the Sygate Firewall if you
> > want firewall functionallity, but it's not standard.
> > (And I don't have the Sygate firewall at this moment).
> >
> > If I run (from the server of course) I also see the open
> > ports. If I run GFI Network Scanner from a different subnet I even see
> > *MORE* (!) ports open than with grc on the machine itself ?!... I
> > guess that GFI's scanner is better ?
> well if you see them open then they are most certainly open. I would
> recommend the nmap scanner.
> if these ports are services only meant for the internal network then this
> is a mayor concern, you really should get a firewall blocking of those
> ports from the internet as a dedicated firewall standing between your
> internal LAN and Internet.
> /svek