Users may find that the sftp server fails with the subsystem request for sftp by user <x> failed, subsystem not found error after upgrading their devices to run Junos OS release 19.1+.

This article confirms that the error is seen because incoming SFTP connections have been disabled globally by default starting in Junos OS Release 19.1R1.

The following error is seen after the device is upgraded to Junos OS release 19.1+.

Feb  8 10:06:13  mx2010-re0 sshd[83912]: Accepted keyboard-interactive/pam for sftp-user from 10.85.175.182 port 54617 ssh2
Feb  8 10:06:13  mx2010-re0 sshd[83915]: subsystem request for sftp by user sftp-user failed, subsystem not found​

Sometimes, you will get the following error message when attempting to sftp from another Junos device:

subsystem request failed on channel 0

Starting in Junos OS Release 19.1R1, incoming SFTP connections have been disabled globally by default.

Prior to Junos OS Release 19.1R1, incoming SFTP connections were globally enabled by default (enabled SSH: set system services ssh).

To globally enable the incoming SFTP connections, configure the sftp-server  statement at the  [edit system services ssh]  hierarchy level in devices running Junos OS release 19.1+.

 # set system services ssh sftp-server

To configure sftp-server in Junos OS Release 19.1+, refer to Configuring sftp-server .

2021-03-09: Technical documentation reference link added