There are 2 locations, HQ and remote. CIFS has been installed to share files over the WAN. It does work really great locally (in the HQ), but when remote users trying to access over the WAN they face weird problems like: none connection at all, wery slow response time. Our 1st idea was to check network performance, but after several tries we found out that without MS ISA, over the same network it works well. WAN works on CISCO switch and routers. Below you will find a diagram.
To make this situation even more weird here is something what we observed:
When we connect to Netapp via 10.7.100.100 we don`t have any problem, but through 10.7.7.100 it doesnt work.
Due to the local policy we cant use working interface (yes, i know its stupid, but what can you do), besides I dont see the reason why
it should work via 1 interface, but not on 2nd one. Interfaces are physicial, not virtualized.
Question: Do you experience similar problems of ISA Server cooperating with NetApp? How to fix the problem? ISA itself have all necessary rules (port 445...),
but even fully opened generate the same errors. On the internet we found some similiar situations and some of them were caused by CISCO, but we think
We ran into something similar to this with another customer yesterday, and from what we can see in packet traces, etc., the ISA Server load-balancing mechanism was resulting in out-of-order packet delivery. We worked-around the issue by disabling IP fastpath (options ip.fastpath). Please note: fastpath gets blamed for all sorts of things that aren't it's fault - it works properly, and if the rest of the network is behaving properly, it is a useful tool. That said, if you get into a situation where something sends from a MAC address, but wants to receive the reply on a different MAC address (which I would argue is promiscuous and inappropriate), disabling fastpath may help.