Using FTP servers is a common way of transferring files between remote devices. Although falling out of favor compared to more secure methods like using an SFTP server, FTP still has widespread use, especially with legacy and proprietary software.
In this guide, we'll briefly explain what FTP is and how to connect to an FTP server, then how to use an FTP client to establish a connection.
What is an FTP server?
An FTP server is a server that enables remote file access, management, and file transfers over a network using the FTP or FTPS protocol. These days, the network is most commonly the internet, and connections will typically use a domain name.
There are a lot of moving parts working behind the scenes to make FTP work. For the purposes of connecting to an FTP server though, what's important is that the local host (your computer or the device you're connecting with) connects with the remote host (in this case, the FTP server). Once the two devices are connected, files can be transferred between them using the FTP protocol.
You can find out more about how FTP works in our article What is FTP and how does it work?
What do you need to connect to an FTP server?
All FTP servers require a few different components to connect:
- FTP server hostname
- Port number
- Username and password
There are several ways to connect via FTP, but the most widely used is by using a dedicated FTP client, which we'll cover in this guide.
FTP server hostname
In order to connect to an FTP server, you need to know which server to connect to. The hostname identifies a specific FTP server so that your device knows which FTP server you want to establish a connection with.
Hostnames can be a numeric IP address or a domain name. Since domain names are easier to share and commonly used for accessing websites, your FTP server hostname will likely have one. Instead of https:// (which specifies the HTTPS protocol), FTP domains will start with FTP. So to connect to a server at couchdropdemo.com, the domain would look like ftp://couchdropdemo.com
Instead of opening these domains in a web browser, you'd instead open them in an FTP client, which we'll cover in more detail during the connection process.
FTP Port
Ports are endpoints on computers for transmitting information. Each computer has thousands of ports for sending/receiving specific data. In the case of FTP, there are at least two ports used for every connection.
The first FTP port is for the FTP commands, known as the command channel. In this context, "commands" can be considered instructions that tell the devices what to do. For example, the put command copies a file from the local machine onto the server. With most FTP clients, you don't need to know the specific commands and instead use a graphical interface to perform actions like uploading, downloading, and deleting.
The other FTP port is the data channel. This is where the actual data itself is transmitted, like the files being transferred.
The way that establishing ports is resolved varies depending on if you are using passive mode or active mode. We won't delve into the differences here, but most modern FTP connections use passive mode, and you can find out more about the technical differences at Active FTP vs Passive FTP.
By default, FTP uses port 21 for sending commands and port 22 for data. However, because these are known defaults and FTP connections are unencrypted without adding additional security, some FTP servers try to reduce the risk by using different ports, though this is considered to have minimal effect.
If you haven't been given a specific FTP port, you can assume that port 21 will be used.
Username and password
The FTP server will ask for a username and password for you to connect. This will need to be created by a server admin and then provided to you. Sometimes, you will be given a one-time password and can change it to a custom password at first login.
Each user will be given a set of permissions that can include read, write, and edit access. Some servers can also enforce more restrictions like restricting access to the server from specific IPs only.
Because FTP isn't meant for secure file transfers, some servers are simply repositories for sharing files and are fine with anyone connecting. However, the FTP protocol requires a username in order to establish a connection. To get around this, some FTP servers support anonymous login.
Anonymous login is a way for anyone to access an FTP server without having their own provisioned username and password. Most commonly, this is done by having the username be 'anonymous' and the password be an email address. This lets anybody access the server who has access to the hostname, and they'll generally only have access to see and/or download files on the server.
Sometimes, instead of using the anonymous method, the server will simply provide a public username and password, something like "guest" and "password", and something they can provide or will be publicly available somewhere, like in a forum post. However, this can create issues if multiple people try to connect using the same account at the same time, which is one reason why anonymous mode is often used instead.
FTP security issues
While FTP is a convenient way to transfer files to or from a remote machine, it shouldn't be used for anything sensitive in nature. Simple FTP connections are unencrypted, meaning that all data transmitted could be seen by anyone snooping on the connection. This includes usernames and passwords, which are sent in plain text.
A good way to decide if FTP is safe for a specific use case is if you would be fine having the files you transfer and the credentials you use posted publicly online for anyone to see. FTP is similar to having a Google Drive file with "anyone with the link can view" permissions. You should only use unsecured FTP over the public internet when this level of access is acceptable.
If you need to transfer important files and only have the FTP protocol available, you should use FTPS (also known as FTP over TLS).
What is FTPS?
FTPS stands for "FTP secure" and is the same FTP protocol with an additional security layer. With FTPS, the FTP protocol employs Transport Layer Security (TLS) to encrypt the data. This will also protect the password when logging in so it isn't exposed.
Using FTPS is much more secure than FTP because of this encryption. However, you should still be cautious of using this protocol if you need to transfer HIPAA files or other sensitive data, as it is considered less secure than transfer protocols designed to be secure, such as SFTP. For a deeper comparison of FTP, FTPS, and SFTP, see our article on FTP vs SFTP.
Since FTPS uses a TLS layer, the server will need to support connecting with this method. You'll also need to specify that you wish to connect using FTPS in your FTP client when you're creating the connection.
How to connect to an FTP server
After you have all the required components, you'll need a way to connect to the server. For this guide, we'll use an FTP client, which is software that allows you to interact with an FTP server. You can see a comparison of popular FTP clients in our article about choosing the best clients for business file transfers.
The exact steps will vary depending on which FTP client you use, but most of them will follow the same general process.
Using an FTP client to connect to an FTP server
To connect to an FTP server, start by opening up the client. You should either be prompted to choose a connection type or have an option to open a connection. Choose FTP as the connection type (or FTPS / FTP over TLS).
You'll then be asked to provide details for the FTP server:
- The hostname will go in a 'hostname' field or something similar. Usually, you won't need to enter the "Ftp://" or "Ftps://" as the client will add that for you since all hostnames include it.
- Most likely, the FTP port field will be filled in with "21" already. Only change this if you were given a different port number (or add it if it isn't there). If you were given a different port, make sure to use the port number for the command channel, not the data channel.
- Add your username and password in the fields. For anonymous logins, some FTP clients include a field to check to tell the client you want to use the anonymous method.
Once you've added all the details, choose to connect and the server will check if you are a validated user.
Establishing the first FTP connection
The first time you connect to an FTP server, most FTP clients will give you a message about the server. When using unencrypted FTP, this may be a warning about having an unsecured connection and a confirmation that you still want to connect. If you're aware of the risks, you can continue to connect and stop the warning from showing again.
After the first connection, you can save the login details like usernames, passwords, or even entire previous connections with many FTP clients. If you need to connect to the same server often you can simplify the connection process this way.
Using Couchdrop to connect to an FTP server
Couchdrop is a cloud FTP server that has no infrastructure management and can also function as an FTP client. Along with support for FTP, Couchdrop supports SFTP, SCP, S3, and AS2 connections, and allows you to transfer files between systems that don't support the same protocol.
There are also many security settings available, such as granular user access controls, feature restrictions, user root isolation, IP restrictions, and account lockout to help make FTP connections more secure.
You can try Couchdrop for FTP for 14 days and get instant access with no credit card required. Sign up for an account now to get started.