Chris and Mark, Regarding MTUs. I'm not working at that knowledge level, so I asked our technical support people...
They said we are not using TCP/IP for transport. Instead, we are using "IPSEC" and the data is both encrypted and encapsulated for transport. Thanks for the "shot in the dark". I'm still looking for the light switch... Mike Patient Solutions Engineer > * Email : [EMAIL PROTECTED] > * Phone: 407.805.1558 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: Thursday, January 24, 2002 8:00 AM To: [EMAIL PROTECTED] Subject: Re: MTU - VNC dies and requires reconnection every few minutes (Win NT - AT T Extranet - Cable Modem) Chris, can you clarify your reply please. On 24/01/2002 11:35:20 Chris Jaecker wrote: > To test for this try sending out pings with 1500 mtu and df set (client to server or vice versa). #ping -? Usage: ping [-t] [-a] [-n count] [-l size] [-f] [-i TTL] [-v TOS] [-r count] [-s count] [[-j host-list] | [-k host-list]] [-w timeout] destination-list Options: -t Ping the specifed host until interrupted. -a Resolve addresses to hostnames. -n count Number of echo requests to send. -l size Send buffer size. -f Set Don't Fragment flag in packet. -i TTL Time To Live. -v TOS Type Of Service. -r count Record route for count hops. -s count Timestamp for count hops. -j host-list Loose source route along host-list. -k host-list Strict source route along host-list. -w timeout Timeout in milliseconds to wait for each reply. ...so that would be ping -l 1500 -f remote_host - correct ? >If it is the problem, try this: > > The solution was to reduce the MTU of the VNC host. This can be done in the registry permanently with: > > HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\<adapter>\Tcpip\Paramet ers\MTU > > which should be set to 1400 [Under NT4 system] I couldn't find any Tcpip\Parameter names under Services and couldn't really match <adapter> to my actual adapter can you advise how to create an appropriate "<adapter>" name please. > The NT server can also be forced to discover the MTU of a path by setting: > > HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters\Enable PMTUBHDetect > On my system, this did not exist, so presumably requires creation. a) what is the behaviour when entry does not exist? b) can you confirm that "discover" means "discover and use" c) As a normal "end-user", when would you NOT want "discover and use" ? I assume it is useful when investigating performance and setting up a network. > which is a REG_DWORD value. Setting it to 1 forces the NT server to > discover the MTU of the path to the target system (in this case the VNC > viewer). If you set the value to 0, it forces the MTU down to 576, and > doesn't attempt to discover the MTU at all. thanks for your advice, Mark ------------------------------------------------------------- --- Visit our Internet site at http://www.reuters.com Any views expressed in this message are those of the individual sender, except where the sender specifically states them to be the views of Reuters Ltd. --------------------------------------------------------------------- To unsubscribe, mail [EMAIL PROTECTED] with the line: 'unsubscribe vnc-list' in the message BODY See also: http://www.uk.research.att.com/vnc/intouch.html --------------------------------------------------------------------- --------------------------------------------------------------------- To unsubscribe, mail [EMAIL PROTECTED] with the line: 'unsubscribe vnc-list' in the message BODY See also: http://www.uk.research.att.com/vnc/intouch.html ---------------------------------------------------------------------
