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The DVG-1120M ATA is also a firewall and therefore blocks all incoming traffic for externally initiated requests. As such, if you have any applications/servers on the DVG's LAN, you will have to set port forwarding on the DVG (below), or other routers connected to the WAN side of your ATA.

Note that since this applies only to requests initiated from the Internet, if you are FTPing from your computer, there are no ports to open since the request is initiated from within your LAN. However, if you want to FTP to your computer from an external site, you need to "forward" ports as noted below.

NOTE: See »www.firewalling.com for further details on Port Forwarding and how to configure various routers including the DVG-1120.


DVG Port Forwarding
Port forwarding allows traffic on a specific port to be passed on. This is handy if you need to access your LAN from a remote location or you want to set up an ftp server.

You should setup a FIXED LAN IP for the computer(s)/server(s) you are forwarding to from the DVG. Note that this address will be determined by the DVG'S LAN IP address which by default is 192.168.15.1 (i.e. Your computer/server can have an address of 192.168.15.2).

Alternatively, you can set a DHCP address range of "one" (1) to force a fixed DHCP address for the device connected to the Ethernet port.

After signing onto the DVG, you need to go to NAT Configuration, and then Local Server Configuration to access the screens for setting up port forwarding.

There are only 6 slots, so if you need to open up TCP and UDP simultaneously for a particular port, then you'll have even fewer left for additional ports.

If you're a heavy BT user then good luck!

An example by Kenmo:

I have the following port forwarding setup working:

cablemodem <-> DVG-1120M <-> Linux firewall/mail/webserver <-> LAN

Inside address range (DVG): 192.168.15.0/24

DVG-1120M IP address (LAN side): 192.168.15.1
Linux box addresses: 192.168.15.9 (DVG side); 192.168.22.254 (LAN side)

LAN address range: 192.168.22.0/24

Ports forwarded in DVG:

Port 22 TCP -> 192.168.15.9 SSH
Port 25 TCP -> 192.168.15.9 SMTP (mail)
Port 80 TCP -> 192.168.15.9 HTTP

For FTP you'd need to forward both 20 TCP and 21 TCP unless the ftp will be passive (PASV) mode, in which case just 21 TCP will suffice.

These serve my needs and give me the QoS feature of the DVG.

Now there's no reason why another router shouldn't work in place of the Linux box I'm using as a router, with those same ports forwarded to a server behind it, or maybe with that server in the router's DMZ. In any case the ports are forwarded to the address of the next machine in the chain, which may not be the final destination, comprendez (as in double NAT with multiple Gateways in sequence) ?

Oh... for those having trouble with getting the DVG to keep the settings, always choose "Continue and 'Restart System' later" after each edit and when you are done editing, choose "Save & Restart System" from the system menu at the left and choose "Yes" when it asks if you want to save the settings. It always works for me!



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by canoe See Profile
last modified: 2006-05-20 11:14:51