Connect to an SFTP server (password or SSH key)

To browse and transfer files on a Linux server, VPS, Raspberry Pi or NAS from your Android phone, connect over SFTP, the file-transfer part of SSH. Any machine you can ssh into almost certainly supports SFTP already, with nothing extra to install. Solid Explorer connects over SFTP with a password or an SSH private key (Ed25519, ECDSA, RSA). It continues interrupted transfers where they stopped and lets you work with server files next to your phone's files in two panels.

What you need

• The server's hostname or IP address, and its SSH port (22 unless it was changed).

• Your username on the server.

• Either your password or an SSH private key file on your phone (or its text in your clipboard).

Add the connection

1. In Solid Explorer, tap the + button at the bottom right of a file panel and choose New connection.

2. Under Connection type, choose SFTP and tap Next.

3. On Server details, fill in:

   1. Server name or IP address, for example myserver.com or 192.168.1.10.

   2. Port number. Already set to 22. Change it only if your server uses a different SSH port.

   3. Path. Leave it empty to start in your home folder, or enter a folder such as /var/www.

   4. Display name. The name shown in Solid Explorer. It defaults to the server name.

4. On Authentication, choose Username and password or SSH private key (see the next section for keys).

5. For a password, enter your Username and Password. Keep Remember password checked if you don't want to type it each time.

6. On Set advanced? choose No. Choose Yes only if file names on your server show up garbled. It lets you pick a different Encoding (UTF-8 is right for almost every server).

7. Check the Review page, tap Next, then on Almost done! tap Connect.

8. The first time, Solid Explorer asks you to trust the server's host key (see "The host key prompt" below). Tap Accept.

9. When the connection test succeeds, tap Finish.

The connection opens straight away and stays in the side menu (drawer) under Storage.

Log in with an SSH key

On the Authentication page, choose SSH private key. On the next page:

1. Enter your Username.

2. Provide the private key (not the .pub file) in one of two ways:

   1. Tap the folder icon next to Select a file with your private key… and pick the key file on your phone, or

   2. Paste the whole key, including the -----BEGIN and -----END lines, into the box under … or paste it here.

3. Continue with Next.

Under the key, Solid Explorer shows its fingerprint SHA256:…). It should match what ssh-keygen -lf yourkey.pub prints on your computer. Keys with a passphrase show no fingerprint until they're unlocked.

Solid Explorer copies the key into the connection, so you can delete the key file from your phone's storage afterwards.

Supported key formats

Converting a PuTTY .ppk key

Open the key in PuTTYgen on Windows and choose Conversions → Export OpenSSH key. On Linux or macOS, run:

puttygen mykey.ppk -O private-openssh -o mykey

Then use the exported file in Solid Explorer.

Creating a new key that works everywhere:

ssh-keygen -t ed25519 -f ~/.ssh/android_key

Add the contents of android_key.pub to ~/.ssh/authorized_keys on the server, and copy android_key (the private key) to your phone.

The host key prompt

The first time you connect, Solid Explorer shows "The server's host key is not cached in the registry and is not trusted" along with the server's key. This is normal SSH behavior and protects you from connecting to an impostor server. If you trust the server, tap Accept. Solid Explorer remembers the key.

To make sure you're talking to the right server, compare the SHA256:… fingerprint in the prompt with the one the server reports. On the server, run:

ssh-keygen -lf /etc/ssh/ssh_host_ed25519_key.pub

Use the file that matches the key type shown in the prompt, for example ssh_host_ecdsa_key.pub or ssh_host_rsa_key.pub. If the fingerprints match, it's safe to accept.

Using the connection

• Two panels. Tap the second panel to make it active and open your phone storage there. Then copy or move files between the server and your phone in either direction.

• Large or interrupted transfers. If the connection drops during a transfer, Solid Explorer retries and continues from where it stopped instead of starting over.

• Properties shows the owner, group and permissions (for example rwxr-xr-x (755)). Changing permissions over SFTP isn't supported.

• Edit, rename or delete the connection. Open the drawer, tap the ⋮ menu at the top and choose Storage manager. Each connection has its own ⋮ menu with Edit, Delete and Create shortcut.

Troubleshooting