This bug has been copied from bug #494428 and has been proposed to be backported to 4.8 z-stream (EUS).
Committed in 89.0.1.EL
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on therefore solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2009-1132.html
Technical note added. If any revisions are required, please edit the "Technical Notes" field accordingly. All revisions will be proofread by the Engineering Content Services team. New Contents: The tcp_ack() function cleared the probes_out variable even if there were outstanding packets. When low TCP keepalive intervals were used, this bug may have caused problems, such as connections terminating, when using remote tools such as rsh and rlogin.