FTP is a way to transfer files online. You might think of the sites you visit in your browser as “the internet,” but your browser only uses one protocol: HTTP. There are many others protocols that, collectively, make up the internet. IMAP and POP, for instance, are two protocols that email clients use to send and receive messages. XMPP is a protocol used to send and receive instant messages. FTP is another such protocol.
FTP stands for “File Transfer Protocol.” It’s also one of the oldest protocols in use today, and is a convenient way to move files around. An FTP server offers access to a directory, with sub-directories. Users connect to these servers with an FTP client, a piece of software that lets you download files from the server, as well as upload files to it.
Many internet users will never have any use for FTP, but if you’re building a website, it’s an essential tool. And because it’s such a fundamental tool on the web, it’s worth knowing about even if you’re not a developer. So, here’s everything the average internet user needs to know about FTP and how to use it.
What is FTP for?
FTP is a useful tool for moving information from the computer you’re working on to the server where a website is hosted. If you want to install WordPress on a web server, for example, you’re going to need FTP to copy the files over.
It’s also occasionally used as a way to share files. One person may upload a file to an FTP server then share a link to it with another person. This sort of usage has become less common in the age of easy-to-use cloud services (these are our favorites) but some people prefer to have their files hosted on a home server, and use FTP to enable that.
FTP is one of the simplest, and earliest formats created to quickly move files from one device to another. It has its origins all the way in 1971, when the first version was created and published by Abhay Bhushan. In the 1980s, the FTP format was updated to the TCP/IP version associated with servers.
FTP uses two basic channels to operate. The command channel carries information about the task itself — what files are to be accessed, if commands are registering, etc. The data channel then transfers the actual file data between devices.
These FTP connections can also have active and passive modes. Active modes are the most common, and allow open communication between the server and the device over both channels, with the server taking an active role in establishing the connection by approving requests for data. However, this mode can be disrupted by firewalls and similar issues, so there’s also a passive mode where the server pays attention but doesn’t actively maintain the connections, allowing the other device to do all the work.
What does FTP look like?
Although it depends on what client you use to manage the files, it essentially looks like the other files on your computer. There’s a hierarchical folder structure, which you can explore in a similar fashion to Windows Explorer or Finder.
You can get an idea of this by browsing a public FTP server. For example, Adobe offers downloads of all its software via FTP, for customers who own software like Photoshop with a valid product key but don’t have their installation CD handy. Browsers such as Chrome and Firefox also support exploring FTP servers (but not uploading files).
On Reddit, r/opendirectories is an entire community dedicated to sharing publicly accessible FTP servers. However, many of these directories are full of pirated content, porn, and a similar combination thereof.
Using FTP to download files in this way is relatively rare. For the most part, FTP is used to upload files from your computer to a server you’re working on.
Is FTP secure?
Not by design, no. FTP dates back to a time long before cybersecurity was much more than a hypothetical field. This means that FTP transfers aren’t encrypted, so it’s relatively easy to intercept files for anyone capable of packet sniffing.
For this reason, many people use FTPS instead. This essentially works in the same manner as FTP, but encrypts everything, meaning prying eyes can’t read any files, even if they could intercept them. At this point, many servers refuse to offer unencrypted access, and instead, offer only FTPS.
Which FTP clients are the best?
FileZilla and CyberDuck are two of our favorites FTP clients which we can recommend wholeheartedly. They’re fully featured and have been around for years, so have established, refined user interfaces and tools to make your FTP transfer process quick and easy. If you want more examples of good FTP clients, check out our guide to the best of the best FTP clients.
Can I set up my own FTP server?
The short answer, is yes. Windows users can download and run FileZilla server. Mac users, meanwhile, don’t need any third-party software. Just head to Sharing in System Preferences, then enable Remote Login. This will enable an FTPS server on your Mac, thus granting you a secure way to browse your computer and grab files with any FTP client.
You’ll need an FTP client installed on another computer in order to browse your files, though. Just use the IP address for the computer you previously set up as a server.
To access files from outside your home network, you’ll need to set up port forwarding on your router. And if you plan on making an FTP server accessible online, it’s a good idea to lock it down with encryption.
For more detailed information on setting up an FTP server on your Android phone or tablet, check out our full guide.