Bug ID 535759: SMTP monitor might mark the server down even if the server answers the HELO message.

Last Modified: Nov 07, 2022

Bug Tracker

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

Known Affected Versions:
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, 12.0.0 HF1, 12.0.0 HF2

Fixed In:
12.1.0, 12.0.0 HF3, 11.6.1

Opened: Jul 28, 2015
Severity: 3-Major
Related Article:


The SMTP monitor marks a server down even when the server responds with a 250 message to the HELO command. Monitor debug output might show the following error messages: -- ERROR: failed to complete the transfer, error code: 28 error message: Time-out. -- ERROR: failed to complete the transfer, error code: 56 error message: Recv failure: Connection reset by peer.


The monitored server is marked down when it is not.


This occurs under any of the following conditions: -- The monitored server does not close the TCP connection (does not send a FIN) after receiving a QUIT command from the client. -- The server does not include the word 'Bye' in the 221 message in response to the 'quit' sent by the BIG-IP system. -- The server issues a RST for any reason after the BIG-IP system has successfully received the 250 response to the HELO message.



Fix Information

SMTP monitor now considers the server up if it receives a successful response to the HELO command.

Behavior Change