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Q: I have a small home network set up
using a NetGear wireless router to connect my computers to my DSL modem and
give me a firewall. I recently created an FTP site (thanks for the
by the way), but I
cannot seem to access it from outside my network. I think that my router is causing the
problem, since this seems like the most logical problem area, and I know it
has a hardware firewall.
I'm still using the default router settings, so I'm guessing there is something I
need to change to allow access from outside the firewall. Any
A: Yes. Most routers use a NAT (Network Address Translation) firewall, which
stops all unsolicited data from
entering the network. When a
computer inside the network requests information from the Internet, the
firewall records the IP address of the computer and that of the Internet
location it is sending data to in a table.
When data comes back from the Internet, the
router compares the IP address of the source to the table and if data had
been requested from that address previously, it is allowed into the network
and sent to the requesting computer.
Obviously, with this type of firewall, no one is going to be able to get
at your FTP site from outside. They
can type in your IP address with an FTP client, but as soon as the request hits
the firewall it will be dropped.
What you need to do is create a virtual server. A virtual server is a set of specific
instructions for your firewall, telling it that if x kind of data is
received from outside the network on y port, it should be allowed into
the network and forwarded to z machine, in your case, the FTP
Any home router that contains a firewall should have a screen for setting
up virtual servers. Consult the
documentation if you have trouble finding it. You will need to set up a virtual server
for TCP port 21 pointing to the IP address of your FTP server. This
should resolve your problem.