FTP Support

Connecting Troubleshooting Network Connectivity Troubleshooting DNS Name Resolution Troubleshooting Connection Time Outs Troubleshooting Corrupted Data Cross Checking Data FTP Clients FTP Scripting Backup Utilities as FTP Tools HTTP Web Access Contact

Connecting:

server:	ftp.ssmi.com
user name:	anonymous
password:	use your email address

Upon connection, expect: "220 Remote Sensing Systems FTP Server..."

Troubleshooting Network Connectivity:

To test basic network connectivity, traceroute to our gateway:

tracert 198.120.16.1

Troubleshooting DNS Name Resolution:

Use a program such as "nslookup" or "ping" to verify that the name is resolving correctly on your computer.

Note that on our FTP server, replying to a ping is disabled.

Ping requests are blocked by our firewall;  they should time out.

This does NOT mean the FTP server is unavailable.

Or, try connecting directly to the ip address: 198.120.16.66

Note, however, that the numerical address may change in the future.

In web browsers, include "ftp://" before the address (e.g. "ftp://ftp.ssmi.com"), or the browser will look for a web site instead of an FTP server.

Troubleshooting Connection Time Outs:

If you seem to be able to log in, but cannot even start downloading files, suspect a passive mode problem.

Find the "passive mode" setting in your FTP client, and try it both ways.

On slow connections and/or noisy lines, timeouts can be problematic. If you are able to download partial files, but interruptions are frequent, look for a program which can resume interrupted downloads. One example is Netscape SmartDownload.

Many FTP clients support resuming interrupted downloads (see below).

Troubleshooting Corrupted Data:

Data files should be downloaded in binary mode.

One of the most common problems occurs when binary data files are downloaded as text (ascii mode), altering and corrupting data.

Many FTP clients will do this by default.

In command line FTP, type "binary" after connecting and before downloading.

In FTP clients, check settings: file extensions are often used to determine binary v. ascii mode.

If you have downloaded data in binary mode, and it still seems corrupt, check file sizes. The number of bytes reported by the FTP server should exactly match the size reported by your local file system. If different, try downloading again.

Cross Checking Data:

The graphic images on this website are produced from the exact same data files that are available on our FTP server. This is an excellent resource for cross checking results. Colors may differ, but values should correlate.

FTP Clients:

FTP clients are programs that connect to and communicate with FTP servers. A host of FTP clients with different GUIs and features are available, some as freeware, most as moderately priced shareware with free trial periods.

Try searching www.download.com for "FTP client".

FTP Scripting:

Some FTP clients on download.com (see above) support automation.

Python (www.python.org) is a free, open-source programming language with a very useful built-in FTP control module. Good capabilities with a moderate learning curve for programmers.

Backup Utilities as FTP Tools:

Many programs designed for backup support FTP.

Example: SyncBackSE (www.2brightsparks.com) is a low cost program which can schedule the synchronization of an FTP directory to a local folder. Only download what's new or changed.

HTTP Web Access:

For alternate access (and another troubleshooting tool), try a web browser (IE, FireFox, etc.):

www.remss.com/data/

Contact:

Marty Brewer

(707) 545-2904 x 24

Last updated: April 22, 2009