Description

This article provides an explanation of the default FTP modes on Junos OS 14.2 and Junos OS 15.1. It also provides an explanation on how to change the mode.

Symptoms

Junos OS 14.2 utilizes FTP ' Active ' mode as default:

user@MX240> ftp xxx.xxx.xxx.xxx
Connected to xxx.xxx.xxx.xxx.
220 yyyyy.juniper.net FTP server (Version 6.00LS) ready.
Name (xxx.xxx.xxx.xxx:yyy): <user>
331 Password required for <user> .
Password:
230 User <user> logged in.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> bin
200 Type set to I.
ftp> cd /homes/ <user>
250 CWD command successful.
ftp> get <filename> .txt
local: <filename> .txt remote: <filename> .txt
200 PORT command successful.
150 Opening BINARY mode data connection for ' <filename> .txt' (144 bytes).
  0% |                       100% |************************************|   144      00:00 ETA
226 Transfer complete.
144 bytes received in 0.02 seconds (5.69 KB/s)
ftp>

Junos OS 15.1 utilizes FTP ' Extended Passive ' mode as default:

user@MX240> ftp xxx.xxx.xxx.xxx
Connected to xxx.xxx.xxx.xxx.
220 yyyyy.juniper.net FTP server (Version 6.00LS) ready.
Name (xxx.xxx.xxx.xxx:yyy): <user>
331 Password required for <user> .
Password:
230 User <user> logged in.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> bin
200 Type set to I.
ftp> cd /homes/ <user>
250 CWD command successful.
ftp> get <filename> .txt
local: <filename> .txt remote: <filename> .txt
229 Entering Extended Passive Mode (|||49727|)
150 Opening BINARY mode data connection for ' <filename> .txt' (144 bytes).
100% |*****************************************************************|   144       5.41 KiB/s    00:00 ETA
226 Transfer complete.
144 bytes received in 00:00 (5.40 KiB/s)
ftp>

Solution

On MX Series (MX240, MX480, MX960, and MX2000), Junos OS 14.2 utilizes 'Active mode' by default, and Junos OS 15.1 utilizes 'Extended Passive mode' by default.

Junos OS 14.2 supports legacy FreeBSD version 6.3, and the Junos OS 15.1 supports FreeBSD version 10. Hence, from Junos OS 15.1, the default FTP mode was changed from 'Active' to 'Extended Passive'.

On the other hand, MX-series (MX80 and MX104) utilizes 'Active' FTP mode as default, regardless of the Junos OS version.

The FTP mode 'Active' or 'Passive' on all Junos OS devices can be changed using the passive off/on switch option.

The FTP mode can be changed by using the passive off/on switch.
ftp>​ passive off   : Active mode
ftp>  passive on  : Extended Passive mode

Junos OS 15.1

user@MX240> ftp xxx.xxx.xxx.xxx
Connected to xxx.xxx.xxx.xxx.
220 yyyyy.juniper.net FTP server (Version 6.00LS) ready.
Name (xxx.xxx.xxx.xxx:yyy): <user>
331 Password required for <user> .
Password:
230 User <user> logged in.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> bin
200 Type set to I.
ftp> cd /homes/ <user>
250 CWD command successful.
ftp> passive
Passive mode: off; fallback to active mode: off.
ftp> passive off
Passive mode: off; fallback to active mode: off.
ftp> get <filename> .txt
local: <filename> .txt remote: <filename> .txt
200 EPRT command successful.
150 Opening BINARY mode data connection for ' <filename> .txt' (144 bytes).
100% |********************************************************************|   144        0.44 KiB/s    00:00 ETA
226 Transfer complete.
144 bytes received in 00:00 (0.44 KiB/s)
ftp>

ftp> passive on
Passive mode: on; fallback to active mode: off.
ftp> get <filename> .txt
local: <filename> .txt remote: <filename> .txt
229 Entering Extended Passive Mode (|||64140|)
150 Opening BINARY mode data connection for ' <filename> .txt' (144 bytes).
100% |********************************************************************|   144        0.66 KiB/s    00:00 ETA
226 Transfer complete.
144 bytes received in 00:00 (0.66 KiB/s)
ftp> 

user@MX240> start shell
% ftp xxx.xxx.xxx.xxx
Connected to xxx.xxx.xxx.xxx.
220 yyyyy.juniper.net FTP server (Version 6.00LS) ready.
Name (xxx.xxx.xxx.xxx:yyy): <user>
331 Password required for <user> .
Password:
230 User <user> logged in.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> passive
Passive mode on.
ftp> passive off
Passive mode off.
ftp> passive on
Passive mode on.
ftp>

Similarly, Junos can alter the FTP mode (active or passive) to send archived files to a FTP server with the following prefixes:

Active FTP: ftp ://
Passive FTP: pasvftp ://

[Active mode]
user@MX240> request support information |save ftp :// <user> : <pwd> @xxx.xxx.xxx.xxx/ <filename> .txt
ftp:// <user> : <pwd> @xxx.xxx.xxx.xxx/ <filename> .txt  100% of  481 kB   11 MBps
Wrote 9263 lines of output to ' ftp :// <user> : <pwd> @xxx.xxx.xxx.xxx/ <filename> .txt'

[Passive mode]
user@MX240> request support information |save pasvftp :// <user> : <pwd> @xxx.xxx.xxx.xxx/ <filename> .txt
pasvftp:// <user> : <pwd> @xxx.xxx.xxx.xxx/ <filename> .txt  100% of  481 kB    9 MBps
Wrote 9263 lines of output to ' pasvftp :// <user> : <pwd> @xxx.xxx.xxx.xxx/ <filename> .txt'

Modification History

2022-11-04: Article reviewed for accuracy. Article is valid and relevant

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