Secure file transfer program (sftp)

wikipedia:Secure file transfer program

Binaries

• /usr/lib/sftp-server
• /usr/bin/sftp

Usage

sftp
usage: sftp [-46aCfpqrv] [-B buffer_size] [-b batchfile] [-c cipher]
          [-D sftp_server_path] [-F ssh_config] [-i identity_file] [-l limit]
          [-o ssh_option] [-P port] [-R num_requests] [-S program]
          [-s subsystem | sftp_server] destination

News

• OpenSSH 9.0 Aug 2022 includes support for server side copies using sftp cp command.

Activities

• Read https://askubuntu.com/a/206376 sftp configuration

Logs

journalctl -u ssh

This service allows sftp connections only.

Example of failed login

May 07 15:28:06 SERVER sshd[1869802]: Connection closed by authenticating user USERNAME 23.33.xx.xx port 12547 [preauth]

Example of failed login with verbose mode, see (sshd logs)

May 07 15:55:01 SERVER sshd[1870524]: Failed none for  USERNAME  from 23.33.xx.xx port 12616 ssh2
May 07 15:55:01 SERVER sshd[1870524]: Failed publickey for  USERNAME  from 23.33.xx.xx port 12616 ssh2: RSA SHA256:tAkCKfvCmOTpVeceSyAOy9Sjyp213hQ7RLTyKUaNw12
May 07 15:55:00 SERVER sshd[1870524]: Connection from 23.33.xx.xx port 12616 on 10.10.10.xx port 22 rdomain ""

Example of successfully session

May 07 15:35:07 SERVER sshd[1870236]: Accepted publickey for USER from xx.xx.xx.xx port 60249 ssh2: ED25519 SHA256:EPEztZnnCh/fPqJ5wlgXUYMMx+LOOIegGdF76galaXw
May 07 15:35:07 SERVER sshd[1870236]: pam_unix(sshd:session): session opened for user USER by (uid=0)
May 07 15:35:07 SERVER systemd-logind[2350]: New session 2668 of user USER.
May 07 15:35:07 SERVER systemd[1]: Started Session 2668 of user USER.

Related terms

• jailkit
• scp, rsync
• Sftp configuration
• internal-sftp directive in sshd_config added in OpenSSH 4.9 (March 30, 2008)
• sshfs
• sftp (command)
• Lftp
• multipass transfer

See also

• sftp, sftp chroot configuration, Filezilla, Core FTP, sshfs, internal-sftp, sshd_config, SFTP protocol, Secure file transfer program (sftp)
• rsync, scp, sftp, rsnapshot, rclone, rdiff
• OpenSSH (changelog): /etc/ssh/sshd_config | /etc/ssh/ssh_config | ~/.ssh/ | openSSL | sshd logs | sftp | scp | authorized_keys | ssh-keygen | ssh-keyscan | ssh-add | ssh-agent | ssh | Ssh -O stop | ssh-copy-id | CheckHostIP | UseKeychain, OpenSSF