Bug ID 1410441: Large file transfer over SFTP/SSH proxy failure

Last Modified: Jul 24, 2025

Affected Product(s):
BIG-IP AFM(all modules)

Known Affected Versions:
16.1.0, 16.1.1, 16.1.2, 16.1.2.1, 16.1.2.2, 16.1.3, 16.1.3.1, 16.1.3.2, 16.1.3.3, 16.1.3.4, 16.1.3.5, 16.1.4, 16.1.4.1, 16.1.4.2, 16.1.4.3, 16.1.5, 16.1.5.1, 16.1.5.2, 16.1.6, 17.1.2, 17.1.2.1, 17.1.2.2

Opened: Dec 05, 2023

Severity: 2-Critical

Symptoms

- Large file transfer (>110MB) fails using the SFTP PUT command through a virtual server configured with AFM SSH Proxy. - Depending on the boundary byte that gets sent from BIG-IP towards the backend server, the server sends back a SSH2_MSG_UNIMPLEMENTED for a packet type corresponding to the incorrect byte being interpreted as the message type.

Impact

File transfer fails.

Conditions

- SSH Proxy profile attached to BIG_IP Virtual Server. - Large file (>110MB) is uploaded using PUT command through the virtual server.

Workaround

Workaround options are: - Limit the file transfer rate through the SFTP client. Ex: sftp -l 1000 <VS-IP> put <filename> - Use a smaller buffer size (eg. 1400). Ex: sftp -B 1400 <VS-IP> put <filename>

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips