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Bernd Michitsch
Hi NG,
I ´ve installed Vista and OL2007...
Basically:
The Microsoft Windows Vista OS enables the TCP Window Scaling option by
default (previous Windows OSes had this option disabled). The TCP Window
Scaling option is described in RFC 1323 (TCP Extensions for High
Performance), and allows for the device to advertise a receive window larger
than 65 K than TCP originally specified. This is useful in the higher speed
networks of today, where more data can be outstanding on the wire before it
is acknowledged. This slow performance, or dropped TCP connections is caused
by some versions of Cisco IOS® Firewall software not supporting the TCP
Window Scaling option. This causes it to have a much smaller TCP window than
the endpoints actually have. This causes the Cisco IOS router that runs the
IOS Firewall feature set to drop packets that it believes are outside the TCP
window, but which really are not.
So, through many firewalls, many protocals fall apart.
And here is a solution, that worked perfectly for me, and several of my
clients clients.
Drop to a command prompt and run:
netsh interface tcp set global autotuninglevel=disabled
If the command returns this response, "Set global command failed on
IPv4 The requested operation requires elevation", then you need to do
this:
Click start (windows symbol), Accessories, right click on "Command
Prompt", then choose "Run as Administrator", then try the netsh
command (above) again.
This problem is occuring for many protocols, POP, IMAP, RDP etc.
Hope this is a little help for you too...
Best Regards,
Bernd
I ´ve installed Vista and OL2007...
Basically:
The Microsoft Windows Vista OS enables the TCP Window Scaling option by
default (previous Windows OSes had this option disabled). The TCP Window
Scaling option is described in RFC 1323 (TCP Extensions for High
Performance), and allows for the device to advertise a receive window larger
than 65 K than TCP originally specified. This is useful in the higher speed
networks of today, where more data can be outstanding on the wire before it
is acknowledged. This slow performance, or dropped TCP connections is caused
by some versions of Cisco IOS® Firewall software not supporting the TCP
Window Scaling option. This causes it to have a much smaller TCP window than
the endpoints actually have. This causes the Cisco IOS router that runs the
IOS Firewall feature set to drop packets that it believes are outside the TCP
window, but which really are not.
So, through many firewalls, many protocals fall apart.
And here is a solution, that worked perfectly for me, and several of my
clients clients.
Drop to a command prompt and run:
netsh interface tcp set global autotuninglevel=disabled
If the command returns this response, "Set global command failed on
IPv4 The requested operation requires elevation", then you need to do
this:
Click start (windows symbol), Accessories, right click on "Command
Prompt", then choose "Run as Administrator", then try the netsh
command (above) again.
This problem is occuring for many protocols, POP, IMAP, RDP etc.
Hope this is a little help for you too...
Best Regards,
Bernd