ToS getting reset to 0 when egress from LTM
Scenario:
Micrsoft Lync front-end servers. Their gateway is on the LTM. Client requests to the front-end are balanced by virtual servers on a variety of ports.
The Lync servers are configured to mark their SSL-TLS SIP traffic (port 5061) as AF31. From packet captures, I have found that the markings are in tact while traversing the link to the LTM back-end network. However, when getting capture from the front-end interfaces, the DSCP has been reset to 0.
I have a TCP profile set on the virtual server that is listening on 5061, which has the options enabled to pass-through ToS and QoS. What else am I missing here?
I found a bug that looks somewhat related, but I am not running a SIP profile and this traffic is TCP.
http://support.f5.com/kb/en-us/solutions/public/14000/000/sol14019.html