Issue with SharePoint 2007 behind BIG-IP LTM 9.4.8

I think Helen hit the nail on the head. In almost all load balanced environments (the exception being the npath/direct server return corner case), return traffic from the servers will need to pass back through the load balancer before it makes it back to the client.

 

 

Most implementations accomplish this by putting the servers 'behind' the BIG-IP, and point the default gateway of the servers at the BIG-IP.

 

 

Others will use SNAT functionality on the BIG-IP to swap out the source IP of the connection as it passes through the BIG-IP on its way to the servers. Now the servers will see the source IP being that of the BIG-IP, and send all return traffic towards it. This option allows you more flexibility in how you configure your servers routing tables, but has the drawback of making it look like all the connections were originated from the BIG-IP.

 

 

So Mike.... I would check 2 things. Are your servers pointing to the BIG-IP as their default gateway? If not, and you dont want to change their routing, check to see if SNAT is enabled on the VIP/BIG-IP.