All Barracuda Web Filters / WSGs, all firmware versions.
Answer:
· Many times an ISP problem exists with their modem or upstream of your network.
· There is a concern that it could be related to your Firewall
· It could be something with any perimeter devices like IDS / IPS
· Even mention of load balancers, DOS and NAT boxes.
Basically the issue is seen as a request was sent out from the filter, upon returning to the filter it was seen as a Zero Sized Reply packet. This was not the web filter stating it has a problem, it is a reply the Web filter acknowledged from a bad packet returned to it.
Many times the ISP will be able to track down where the issue is and help to resolve the problem experienced.
ADDITIONAL NOTES:
See article here, on Zero sized possible fixes
Link to this page:
https://campus.barracuda.com/solution/50160000000uJPDAA2