On 2011-05-23, * VLGroup Forums <[email protected]> wrote: > > So, in short ` a remote location, with a Windows 2008 R2 server, connecting to > it from a different location, with a XP SP3 machine works fine (RDP), from the > same different location with a Windows 7 RDP it does not.
I think RDP is a red herring, I expect this is to do with different TCP behaviour on newer versions of Windows, specifically that it now uses window scaling so that larger TCP buffers can be used. The wscale information (only present in TCP SYNs) is needed to handle sequence number tracking, so it's important to create states on the SYNs and not intermediate packets later in the session, so in 2006 we changed defaults so that 'pass' rules now use an implicit "flags S/SA keep state" which avoids most problems relating to this.
