Bug ID 539270: A specific NTLM client fails to authenticate with BIG-IP

Last Modified: Oct 06, 2020

Bug Tracker

Affected Product:  See more info
BIG-IP APM(all modules)

Known Affected Versions:
11.3.0, 11.4.0, 11.5.1, 11.5.1 HF1, 11.5.1 HF10, 11.5.1 HF11, 11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.5.1 HF5, 11.5.1 HF6, 11.5.1 HF7, 11.5.1 HF8, 11.5.1 HF9, 11.5.10, 11.5.2, 11.5.2 HF1, 11.5.3, 11.5.3 HF1, 11.5.3 HF2, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5, 11.6.0 HF6, 11.6.0 HF7, 11.6.0 HF8, 12.0.0

Fixed In:
12.1.0, 12.0.0 HF1, 11.6.1, 11.5.4

Opened: Aug 12, 2015
Severity: 3-Major


Specific NTLM client (such as Android Lync 2013) fails to authenticate with BIG-IP as it sends a particular NTLMSSP_NEGOTIATE which BIG-IP was not able to parse properly and throws an error. This effectively stops the authentication process, and this particular client never completes the authentication.


Cannot complete the authentication, hence, not allowed to access protected resources.


Specific NTLM client. It is not clear whether this issues affect a particular version of Android Lync 2013 or a particular Android version.


No workaround exists for the affected clients.

Fix Information

The BIG-IP system now processes NTLM requests for affected Lync clients, and users of the client are able to authenticate.

Behavior Change