Re: Problem with VPN's on ISA Server 2004 SP1

I had the same problem with Windows SP1. You should remove it.



Jean
"Stefan Cuypers" <stefan.cuypers@xxxxxxxxxxxxxxxx> wrote in message
news:euHJIQyXFHA.2996@xxxxxxxxxxxxxxxxxxxxxxx
> I've been spitting through network monitor trace files this weekend to try
> to locate this problem and the root cause seems to be in my Internet
> connection. While uploading full size packets to the Internet, the number
> of packets that get dropped is quite high, causing the TCP connections to
> time out.
> I still wonder why this was not happening before all the SP1 upgrades
> though. I guess some change (or optimisation?) in the TCP handling now
> brings out the problem.
> I'll look further into this with my Internet provider.
>
> regards,
> Stefan Cuypers
>
>
> "Stefan Cuypers" <stefan.cuypers@xxxxxxxxxxxxxxxx> wrote in message
> news:%237yniKfXFHA.3716@xxxxxxxxxxxxxxxxxxxxxxx
>> I've done a number of upgrades on our network and ever since I'm having
>> problems sending large amounts of data over VPN connections. This shows
>> best when doing a file copy over the VPN connection. Before the upgrades
>> this went fine. After the upgrades we get a Semaphore Timeout Error
>> during the copy. We also get occasional problems trying to connect via
>> terminal services over the VPN's.
>> I think the problem is in ISA Server 2004 SP1 (which is handling the
>> VPN's). Anybody else seen this behaviour and have a solution for it?
>>
>> Here's some history:
>> - installed Windows Server 2003 SP1 on an internal test server
>> - we noticed problems when we connect from the test server over a VPN
>> connection towards a Win2003 Server for server management. We then
>> installed ISA Server 2004 SP1, which seemed to solve this problem
>> - at about the same time we and a number of our customers started to have
>> all kinds of problems communicating to machines over VPN. We tracked this
>> down and installed hotfix 898060 on our servers (not yet on our ISA
>> Server), which solved these problems
>> - then we noticed the copy problem mentioned above, which occured from
>> our workstations and servers
>> - we then installed Windows Server 2003 SP1 on the ISA Server box and
>> applied hotfix 898060, but the problem stayed exactly the same
>>
>> Doing a network monitor trace the problem seems to be a network packet
>> that never gets to the destination. All traffic runs well (with now and
>> then a packet loss causing a retry) up to a certain point where an IP
>> packet does not arrive at the destination, although it is retried 5 times
>> before giving up.
>>
>> We've then done the following tests:
>> - connect a PC directly to the Internet, bypassing ISA Server: things
>> work fine
>> - test at a customers site between 2 machines that have an ISA Server
>> 2000 between them: things work fine
>> - the same machines that work fine in the scenarios above fail though
>> when we run it over the ISA Server 2004 SP1 (we tested L2TP, PPTP VPN's
>> and IPSec tunnelling connections, all have the same problem)
>>
>> Any help would be greatly appreciated.
>>
>> regards,
>> Stefan Cuypers
>>
>>
>>
>>
>
>


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