Webmail Session times out after 5mins of inactivity

We're seeing very strange results with this setup now.

 

 

We're load balancing 4 webmail servers using fastL4 profile with source address persistence. I'm seeing my webmail session time out on 5mins so I'm thinking this is great because it must be matching the idle timeout of the fastL4 profile which is set to 300 seconds. To further test this out, I changed the idle timeout to be 30secs - but what do you know, it's not timing out after 30secs of my webmail session being idle but at 5mins again. I don't get it. We're not using any SNAT so you can rule out that timeout. The only other option is the VLAN group but I don't even think that comes into play based on the the line below.

 

 

https://support.f5.com/kb/en-us/solutions/public/7000/600/sol7606.html

 

 

"In a VLAN group configuration, traffic that does not match a configuration object, such as a virtual server or SNAT, is handled by the Layer 2 (L2) forwarding proxy."

 

 

http://devcentral.f5.com/Default.aspx?tabid=63&articleType=ArticleView&articleId=189

 

 

Option | Default in seconds | Configurable?

 

Protocol profiles (tcp, fastHTTP, or fastL4) 300 Y

 

Protocol profile (udp) 60 Y

 

SNAT / SNATpool 300 Y

 

SNAT automap 300 N

 

VLAN group 300 N

 

 

Any ideas ?

 

 

Thanks.

 

 

Andy