I missed that - although I've personally seen evidence that leads me to believe the default is 0, not 1.
-------------------------------------------------------------- Roger D. Seielstad - MTS MCSE MS-MVP Sr. Systems Administrator Inovis Inc. > -----Original Message----- > From: Reasoner, Bob (PHES) [mailto:[EMAIL PROTECTED] > Sent: Friday, May 21, 2004 8:42 AM > To: Exchange Discussions > Subject: RE: Latency Issue Exch03 - Outlook > > The important part of that article is that the "Key" doesn't > exist, but it > is the default setting on 2000 and higher, so it is assumed > to exist in its > absence. Creating the Key and enabling it shouldn't actually change > anything as it is the default setting for all interfaces. > > That particular article if you follow it would have you set > that key to 0 > which is OK, but only if you use the other article to hard > code your MTU at > the appropriate size as disabling the discovery key creates a > very low MTU > for off local network transmissions. > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On > Behalf Of Roger > Seielstad > Sent: Friday, May 21, 2004 7:05 AM > To: Exchange Discussions > Subject: RE: Latency Issue Exch03 - Outlook > > For most clients, its more effective to set the following > registry key: > HKLM\System\CCS\Services\TCP\Parameters > EnablePMTUDiscovery to 1 (doesn't exist by default) > > More info on that particular tweak (plus a few others) is > available here: > http://support.microsoft.com/default.aspx?scid=kb;en-us;q31566 > 9&sd=tech > > > -------------------------------------------------------------- > Roger D. Seielstad - MTS MCSE MS-MVP > Sr. Systems Administrator > Inovis Inc. > > > > -----Original Message----- > > From: Dave Vantine [mailto:[EMAIL PROTECTED] > > Sent: Friday, May 21, 2004 7:43 AM > > To: Exchange Discussions > > Subject: RE: Latency Issue Exch03 - Outlook > > > > Most people probably know this but I ran across this information on > > TechRepublic a few months ago on determining the ideal MTU size and > > was surprised to see the results when I followed the > instructions and > > tested some connections. Thought I would pass it on for what its > > worth. > > > > -Dave Vantine > > > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> > > >>>>>>>>>> > > >>>>>>>>>> > > > > Adjusting the Maximum Transmission Unit size Of all the registry > > tweaks that I've found for TCP/IP, perhaps the most useful is the > > ability to adjust the Maximum Transmission Unit (MTU) size. > MTU size > > dictates the maximum packet size (in bytes) that the TCP/IP > transport > > will attempt to transmit over the underlying network. > > Networks that use Internet Connection Sharing (ICS) or > Point-to-Point > > Protocol over Ethernet (PPPoE) for their broadband connections must > > have an MTU size of 1,492 or lower to run efficiently. > > > > An incorrect MTU size can make your network run slowly. > Administrators > > tend to dismiss this problem as low bandwidth on the ISP's end, and > > that might be a source of the problem. But you'd be > surprised at the > > difference an MTU adjustment can make. > > > > The MTU is such a factor because, by default, Windows 2000 > and Windows > > XP set the MTU size to 1,500. It's been my experience that if a > > network is running slowly, even the 1,492 value I mentioned > earlier is > > too high. > > I usually have the best luck by setting the MTU to around 1,454. > > > > You can check the MTU size for your environment by opening > a command > > prompt on your administration workstation and typing PING -F -I > > <MTUsize> <gateway> > > > > where MTUsize is the size you want to experiment with and > gateway is > > the gateway of your network. Start out by using an MTU size > of 1,454. > > Doing so will make the command look something like this: > > PING -F -I 1454 147.100.100.50 > > > > When you enter the command, the PING will either be > successful or it > > will fail with a message stating that the data must be > fragmented. If > > you receive the error message, decrease the MTU value and > keep trying > > until you find a value that works. If the PING command > works the first > > time, try incrementing the value by five or 10 until you > see the error > > message. You can then narrow down to the appropriate value. > > > > Once you've discovered an MTU size that works, the next trick is to > > embed the value into the registry. The key's actual location within > > the registry varies depending on the version of Windows > you're using. > > If you're using Windows NT, the MTU key is located at: > > HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services > > \Parameters\Tcpip > > > > If you're using Windows 2000 or higher, the MTU key is located at: > > HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services > > \Tcpip\Parameters\Interfaces\adapter ID > > > > There's a good chance that the MTU key doesn't presently > exist in your > > system and that you'll have to create it at the specified > location. To > > do so, open the Registry Editor and create a new DWORD value called > > MTU. > > The minimum value for this key is 68, and the maximum value > is the MTU > > for the underlying network. > > > > > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> > > >>>>>>>>>> > > >>>> > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf Of > > Horner, Josh > > Sent: Thursday, May 20, 2004 1:38 PM > > To: Exchange Discussions > > Subject: RE: Latency Issue Exch03 - Outlook > > > > The VPN is most likely using an MTU Size Outlook doesn't > like. This > > might be useful. > > > > http://support.microsoft.com/default.aspx?scid=kb;EN-US;329918 > > > > > > Josh > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf Of > > David, Andy > > Sent: Thursday, May 20, 2004 1:11 PM > > To: Exchange Discussions > > Subject: RE: Latency Issue Exch03 - Outlook > > > > > > MTU size is often a culprit with VPNs. > > > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf Of > > Crista Murphy > > Sent: Thursday, May 20, 2004 1:12 PM > > To: Exchange Discussions > > Subject: Latency Issue Exch03 - Outlook > > > > We have a large WAN with remote offices connecting to the > > exch03 office > > via > > PIX 501 to Sonicwall VPN. We are noticing severe latency > problems in > > 90% of our remote offices when trying to use Outlook (2k > std & pro and > > XP) which has shown up in conjunction with the move from the PIX to > > PIX VPN to the current configuration. > > > > Anyone have any suggestions on which diag logging to turn up on the > > exch server that might help diagnose this problem? The people in > > charge of the vpn's are 100% blaming the exch server for dropping > > sessions. > > > > Exch works fine in the local office and via webmail, it is > only when > > connecting thru the VPN with Outlook. > > > > Thanks! > > > > _________________________________________________________________ > > List posting FAQ: http://www.swinc.com/resource/exch_faq.htm > > Web Interface: > > http://intm-dl.sparklist.com/cgi-bin/lyris.pl?enter=exchange&t > > ext_mode=& > > lang > > =english > > To unsubscribe send a blank email to > > %%email.unsub%% > > Exchange List admin: [EMAIL PROTECTED] > > To unsubscribe via postal mail, please contact us at: > > Jupitermedia Corp. > > Attn: Discussion List Management > > 475 Park Avenue South > > New York, NY 10016 > > > > Please include the email address which you have been contacted with. > > > > > > _________________________________________________________________ > > List posting FAQ: http://www.swinc.com/resource/exch_faq.htm > > Web Interface: > > http://intm-dl.sparklist.com/cgi-bin/lyris.pl?enter=exchange&t > > ext_mode=& > > lang > > =english > > To unsubscribe send a blank email to > > %%email.unsub%% > > Exchange List admin: [EMAIL PROTECTED] > > To unsubscribe via postal mail, please contact us at: > > Jupitermedia Corp. > > Attn: Discussion List Management > > 475 Park Avenue South > > New York, NY 10016 > > > > Please include the email address which you have been contacted with. > > > > > > _________________________________________________________________ > > List posting FAQ: http://www.swinc.com/resource/exch_faq.htm > > Web Interface: > > http://intm-dl.sparklist.com/cgi-bin/lyris.pl?enter=exchange&t > > ext_mode=& > > lang=english > > To unsubscribe send a blank email to > > %%email.unsub%% > > Exchange List admin: [EMAIL PROTECTED] > > To unsubscribe via postal mail, please contact us at: > > Jupitermedia Corp. > > Attn: Discussion List Management > > 475 Park Avenue South > > New York, NY 10016 > > > > Please include the email address which you have been contacted with. > > > > This email and any files transmitted with it are confidential and > > intended solely for the use of the individual or entity to > whom they > > are addressed. 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