Hi,

Thanks for the explanation and links to earlier posts.  
I will be reading them closely.

And now I know I _can_ have a tunnel from PSN to PRO.

cheers,

adrian


On 27 Mar 2002 at 9:02, Mike Burden wrote:

> The tunnel tells the GNAT Box that any traffic directed
> to  AAA.BBB.CCC.DDD/PPP  should be forwarded to
> EEE.FFF.GGG.HHH/ppp
> 
> Where:
> AAA.BBB.CCC.DDD  is a GNAT Box address or alias
> PPP  is the port number that the traffic is directed to
>      (21=ftp, 23=telnet, 80=http, 110=pop3, etc)
> EEE.FFF.GGG.HHH  is the IP address of the server
>      that the traffic should be forwarded to
> ppp  is the port number on the server that the traffic
>      should be forwarded to.  This is usually the same
>      as  PPP  but doesn't have to be (but that's an
>      advanced topic)
> 
> 
> The filter tells the GNAT Box who is allowed to use the
> tunnel.  Remote Access Filters *ALWAYS* control access
> to a GNAT Box address or alias.
> 
> 
> Example:
> Your GNAT Box has the EXT address:  203.44.223.1
> You have added an alias:            203.44.223.2
> Your DNS server resolves  www.yourcompany.com  as  203.44.223.1
> Your DNS server resolves  ftp.yourcompany.com  as  203.44.223.1
> Your DNS server resolves  news.yourcompany.com as  203.44.223.2
> 
> Your webserver is on the PSN with the address  192.168.1.2
> Your ftp server is on the PSN with the address  192.168.1.3
> Your news server runs on the same server as ftp
> 
> You would create the following under NAT -> Inbound Tunnels:
> Protocol  From IP Address  Port   To IP Address    Port
> --------  ---------------  -----  ---------------  -----
> TCP       203.44.223.1     80     192.168.1.2        80
> TCP       203.44.223.1     21     192.168.1.3        21
> TCP       203.44.223.2     119    192.168.1.3        119    
> 
> For each of these tunnels, you can either check the "Automatic
> Accept All" box, or you can create a Remote Access Filter to
> control access.  If you choose to create a filter, you would
> create one with a "Destination" IP address of  203.44.223.1
> (for the first two tunnels) or  203.44.223.2  (for the "news"
> tunnel).
> 
> When a host on the Internet makes an HTTP connection to
> 203.44.223.1,  the connection is forwarded to  192.168.1.2
> (this happens invisibly to the user on the Internet).
> 
> If a host on the Internet makes an FTP connection to the
> same address, the connection is forwarded to  192.168.1.3.
> 
> 
> A tunnel can also be used to tunnel from the GNAT Box
> PSN address (or an alias on the PSN interface) to an
> address on the PRO.  You want to use this with caution,
> however, because every tunnel you create from the PSN
> to the PRO is a vulnerability.  How big of a vulnerability
> depends on what you are tunneling.  Tunneling SMTP
> from your mailserver on the DMZ to the mailserver on
> the PRO is probably an acceptable risk to get the
> functionality you want.  Tunneling NETBIOS is (in my
> opinion) always an unacceptable security risk.
> 
> 
> Here's a bit of a tutorial on NAT, Tunnels, and Filters
> that I posted to this group on 1/14/2000:
> http://www.gnatbox.com/gb-users/2000-01/msg00071.html
> 
> As long as I'm at it, here's one on why you need two
> DNS servers when you have NAT:
> http://www.gnatbox.com/gb-users/1999-11/msg00029.html
> 
> 
> The index for the archive (which you may need if you
> want to read the messages I was replying to) is:
> http://www.gnatbox.com/gb-users/
> 
> 
> Mike Burden
> Lynk Systems
> http://www.lynk.com
> (616)532-4985
> [EMAIL PROTECTED]
> 
> 
> 
> > -----Original Message-----
> > From: Adrian Bolzan [mailto:[EMAIL PROTECTED]] 
> > Sent: Tuesday, March 26, 2002 10:28 PM
> > To: [EMAIL PROTECTED]
> > Subject: RE: [gb-users] IP Pass through question
> > 
> > 
> > 
> > 
> > On 26 Mar 2002 at 8:18, Mike Burden wrote:
> > 
> > > Just a quick add-on note:
> > > 
> > > In general, when you want to pass inbound traffic
> > > (EXT to PSN or PSN to PRO), don't think IP Passthrough,
> > > think tunnel and filter.  It's a very rare case when
> > > you actually need IP Passthrough.
> > > 
> > 
> > I did not think I could use a filter that allowed access 
> > directly from
> > the PSN to the PRO.  In fact, I just tried it and it did not 
> > work.
> > 
> > I do not understand the need for a tunnel (by my 
> > understanding of
> > "tunnel" I assume an Inbound Tunnel is meant). Do I need 
> > to set one up
> > on the PSN NIC to allow traffic directed at the PSN NIC on 
> > a certain
> > port/ports to be tunnelled to a server on the PRO network?  
> > 
> > And, can the PSN NIC support Aliases?
> > 
> > This has been an area that I have never fully understood- 
> > how to get
> > traffic directly from the PSN to the PRO, without going via 
> > the EXT
> > NIC.
> > 
> > Any assitance would be appreciated (e.g. what i have to 
> > set up).  
> > 
> > thanks,
> > 
> > adrian
> > 
> > 
> > 
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