FTP Access through Catalyst 1900 Series

Unanswered Question
Aug 23rd, 2007

I apologize if this is the wrong section to post about, I can redirect this message somewhere else if needed.

First, I wont pretend to know a whole lot about networking, because in reality, I don't.

Here is the situation:

A small printing business has decided to begin archiving all of their jobs onto a 2tb LaCie network storage device.

The LaCie device has been configured correctly to be accessed from all computers on the network, as well as allows FTP connections from all of those systems.

However, there is need for FTP access outside the LAN environment and I feel that the Cisco Catalyst 1900 Series switch is not allowing outside connections to access the LaCie Storage Drive.

The company is not concerned about security issues, for no sensitive data will be stored on the drive, and most of the individuals there are not entirely computer savvy when it comes to working outside of their graphic design programs.

I've been through many of the Cisco Catalyst 1900 manuals, but I cant make much sense of the topics that I need to concern myself.

I simply need the switch to accept connections from computers outside the network who are trying to access the LaCie storage device. I'm not sure if this is an issue with the Cable Modem they have installed, or simply an issue with the switch.

If any further info is required, be sure to let me know.

Any help or advice would be greatly appreciated!

I have this problem too.
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steve.busby Fri, 08/24/2007 - 02:20

The Catalyst probably isn't blocking any traffic, more than likely it is in how the network is setup.

Can you describe or perhaps provide a diagram which shows how the equipment is connected?

Besides the cable modem, do they also have a router (Linksys, D-Link, etc) between the cable modem and Catalyst 1900? If so, then depending on which manufacturer they are using, look for "port forwarding" in the user manuals or website documentation.



myfingerhurts Fri, 08/24/2007 - 12:45

They do not have any other connections between the cable modem and the Catalyst switch.

I have provided a diagram showing all of the equipment that is run through the network.

The LaCie Network Storage Device has Windows XP Embedded and has the FTP software pre-loaded. Like I said, I can access the FTP perfectly on the network, but when I attempt to connect to the IP outside of the network, no connection can be made.

steve.busby Fri, 08/24/2007 - 13:21

Thanks for the clarification.

I'm now curious what IP range is on the internal network. Are they using a private IP range or does the user actually pay for internet routable IP addresses for all their devices?

myfingerhurts Fri, 08/24/2007 - 13:31

I'm pretty sure it is simply a private IP range assigned by a Dynamic DNS. From what I know is that they pay for a standard Digital Cable service, that is split at the switch to all of the other devices that can support it.

I simply need ONE computer to be able to access that LaCie storage device from an off-site machine.

I assume that when I'm on the LAN, that I use the LaCie Storage's IP address to connect. (I've been doing that and it's accessed the FTP without a problem.) Wouldnt I have to use the IP address of the Catalyst 1900 Switch when I am trying to access the network from an off-site machine?

If there are any components that are missing from the network, be sure to let me know, and I can arrange to have those picked up and installed.

Thanks for you patients thus far.

steve.busby Sat, 08/25/2007 - 06:44

The Catalyst 1900 is simply a layer 2 device which provides no layer 3 or higher functionality. The IP address of the 1900 is simply there for administrative access into the switch. When you access the LaCie storage device from the LAN, the 1900 simply passes the layer 2 frame from one device to the other (based on MAC address).

There are several possibilities why the user outside can not get access into the LAN.

1) Is the Catalyst 1900 really a Catalyst 1900?

2) Is the cable modem just a cable modem or does it also provide address translation or firewall services?

3) Does your customer have a proxy server or perhaps they are sharing their internet connection on one of their workstations?

Since you're pretty sure they have a private IP range, then to get on the Internet, there has to be something between the Catalyst 1900 and their ISP (besides the cable modem)...ISP...is it possible the ISP is providing address translation?

One final question for now; do all the computer systems on their LAN (except printers, etc) have internet access?

Don't worry, I have lots of patience; like many who answer questions here we enjoy the questions that make us think and research.


myfingerhurts Sat, 08/25/2007 - 08:52

I think I may have it narrowed down, but I'll answer your questions first:

1: Yes I am sure that it is, in fact, a Catalyst 1900 Series 24 port switch.

2: Just found out that the cable modem is a gateway, and has the functionality of a router and has wireless capabilities.

3: No proxy, and no machine is sharing.

All 10 of the computing machines can access the internet.

Could my problem be here:


Apparently they arent using your run-of-the-mill cable modem, because this thing has a few bells and whistles.


Should I try to use the port forwarding on the cable modem and see if that works?

steve.busby Sun, 08/26/2007 - 06:11


In my first response I mentioned "...then depending on which manufacturer they are using, look for "port forwarding" in the user manuals or website documentation."

So you would forward your FTP requests to your LaCie storage device's IP address. Your external customer would ftp to the external IP address of the cable modem, which in turn would forward the request on to the LaCie storage device.



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