VPN and FTP stability

[Bill]

I have a Win2K workstation at one location. It is set up so I can VPN into
the box and once I an logged in, I can FTP through the tunnel to the IIS FTP
server set up there. I use CuteFTP to upload and download files when I
travel. Both sides are using a broadband connection.

I have three related problems.

1. Sometimes the FTP connection fails even though the VPN connection is
still connected.
2. In that case when I am uploading, the IIS FTP server is supposed to be
able to continue broken connections. I can see that the partial file remains
for a while. But if I try to resume I am told that the file cannot be opened
because some process is still accessing it. Eventually, FTP server deletes
it and I must start over.
3. Sometimes the VPN connection itself breaks for no apparent reason. Of
course the FTP client then fails it's upload. If I try to reconnect as soon
as I notice, sometimes I can't get in right away and sometimes I can. But
I'm rarely sure how much time passed between the connection breaking and
trying to reconnect it.

So, what might be causing these connections to break? I have guessed that
something in the protocol might be timing out. If that's a possibility, is
there any way to increase the timeouts, either through a dialog or the
registry? And is there any way to get IIS FTP server to keep the files so
they can be resumed?

Thanks...

 

[Robert L [MS-MVP]]

I would check the MTU size first.

VPN connection issues after Windows 2003 SP1 Resolution: Set my VPN client MTU to 1400. To modify MTU, please refer to this page, How to change MTU settings for PPP or VPN. Related Topics ...
www.howtonetworking.com/casestudy/2003sp1&mtu.htm


Black screen when rdp over vpn Finally, We reduce MTU from 1500 to 1400 in the SonicWall. Then he can use RDC over VPN. Related Topics. How to change MTU ...
www.howtonetworking.com/casestudy/mtu1.htm



Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com
"Bill" <don't want any spam> wrote in message I have a Win2K workstation at one location. It is set up so I can VPN into
the box and once I an logged in, I can FTP through the tunnel to the IIS FTP
server set up there. I use CuteFTP to upload and download files when I
travel. Both sides are using a broadband connection.

I have three related problems.

1. Sometimes the FTP connection fails even though the VPN connection is
still connected.
2. In that case when I am uploading, the IIS FTP server is supposed to be
able to continue broken connections. I can see that the partial file remains
for a while. But if I try to resume I am told that the file cannot be opened
because some process is still accessing it. Eventually, FTP server deletes
it and I must start over.
3. Sometimes the VPN connection itself breaks for no apparent reason. Of
course the FTP client then fails it's upload. If I try to reconnect as soon
as I notice, sometimes I can't get in right away and sometimes I can. But
I'm rarely sure how much time passed between the connection breaking and
trying to reconnect it.

So, what might be causing these connections to break? I have guessed that
something in the protocol might be timing out. If that's a possibility, is
there any way to increase the timeouts, either through a dialog or the
registry? And is there any way to get IIS FTP server to keep the files so
they can be resumed?

Thanks...

 

[MoiToo]

Seconded

You can often prove a VPN throughput issue (usually MTU) by running a ping -t to the terminating VPN server. Usually, when the ping is going, the VPN won't drop at all - but if the ping stops, the VPN is again flakey.

The VPN included with RRAS seems to have many instabilities which are undocumented. PSS seem unable to troubleshoot any better than I can (in Australia anyway).
I would check the MTU size first.

VPN connection issues after Windows 2003 SP1 Resolution: Set my VPN client MTU to 1400. To modify MTU, please refer to this page, How to change MTU settings for PPP or VPN. Related Topics ...
www.howtonetworking.com/casestudy/2003sp1&mtu.htm


Black screen when rdp over vpn Finally, We reduce MTU from 1500 to 1400 in the SonicWall. Then he can use RDC over VPN. Related Topics. How to change MTU ...
www.howtonetworking.com/casestudy/mtu1.htm



Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com
"Bill" <don't want any spam> wrote in message I have a Win2K workstation at one location. It is set up so I can VPN into
the box and once I an logged in, I can FTP through the tunnel to the IIS FTP
server set up there. I use CuteFTP to upload and download files when I
travel. Both sides are using a broadband connection.

I have three related problems.

1. Sometimes the FTP connection fails even though the VPN connection is
still connected.
2. In that case when I am uploading, the IIS FTP server is supposed to be
able to continue broken connections. I can see that the partial file remains
for a while. But if I try to resume I am told that the file cannot be opened
because some process is still accessing it. Eventually, FTP server deletes
it and I must start over.
3. Sometimes the VPN connection itself breaks for no apparent reason. Of
course the FTP client then fails it's upload. If I try to reconnect as soon
as I notice, sometimes I can't get in right away and sometimes I can. But
I'm rarely sure how much time passed between the connection breaking and
trying to reconnect it.

So, what might be causing these connections to break? I have guessed that
something in the protocol might be timing out. If that's a possibility, is
there any way to increase the timeouts, either through a dialog or the
registry? And is there any way to get IIS FTP server to keep the files so
they can be resumed?

Thanks...

 

[Bill Brehm]

I changed the MTU size. I ended up with 1372 being the largest that could use without fragmenting. But when i tested the VPN still dropped. I am now testing it with ping -t.

The size of the file I am trying to upload is 100MB, if that matters, so it takes a couple hours.

RRAS is part of Windows Server, isn't it? I am using the VPN in Win2K workstation.
Seconded

You can often prove a VPN throughput issue (usually MTU) by running a ping -t to the terminating VPN server. Usually, when the ping is going, the VPN won't drop at all - but if the ping stops, the VPN is again flakey.

The VPN included with RRAS seems to have many instabilities which are undocumented. PSS seem unable to troubleshoot any better than I can (in Australia anyway).
I would check the MTU size first.

VPN connection issues after Windows 2003 SP1 Resolution: Set my VPN client MTU to 1400. To modify MTU, please refer to this page, How to change MTU settings for PPP or VPN. Related Topics ...
www.howtonetworking.com/casestudy/2003sp1&mtu.htm


Black screen when rdp over vpn Finally, We reduce MTU from 1500 to 1400 in the SonicWall. Then he can use RDC over VPN. Related Topics. How to change MTU ...
www.howtonetworking.com/casestudy/mtu1.htm



Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com
"Bill" <don't want any spam> wrote in message I have a Win2K workstation at one location. It is set up so I can VPN into
the box and once I an logged in, I can FTP through the tunnel to the IIS FTP
server set up there. I use CuteFTP to upload and download files when I
travel. Both sides are using a broadband connection.

I have three related problems.

1. Sometimes the FTP connection fails even though the VPN connection is
still connected.
2. In that case when I am uploading, the IIS FTP server is supposed to be
able to continue broken connections. I can see that the partial file remains
for a while. But if I try to resume I am told that the file cannot be opened
because some process is still accessing it. Eventually, FTP server deletes
it and I must start over.
3. Sometimes the VPN connection itself breaks for no apparent reason. Of
course the FTP client then fails it's upload. If I try to reconnect as soon
as I notice, sometimes I can't get in right away and sometimes I can. But
I'm rarely sure how much time passed between the connection breaking and
trying to reconnect it.

So, what might be causing these connections to break? I have guessed that
something in the protocol might be timing out. If that's a possibility, is
there any way to increase the timeouts, either through a dialog or the
registry? And is there any way to get IIS FTP server to keep the files so
they can be resumed?

Thanks...

 

[Bill]

Even with the ping -t it still drops the VPN connection. Do you have other possible ideas?
Seconded

You can often prove a VPN throughput issue (usually MTU) by running a ping -t to the terminating VPN server. Usually, when the ping is going, the VPN won't drop at all - but if the ping stops, the VPN is again flakey.

The VPN included with RRAS seems to have many instabilities which are undocumented. PSS seem unable to troubleshoot any better than I can (in Australia anyway).
I would check the MTU size first.

VPN connection issues after Windows 2003 SP1 Resolution: Set my VPN client MTU to 1400. To modify MTU, please refer to this page, How to change MTU settings for PPP or VPN. Related Topics ...
www.howtonetworking.com/casestudy/2003sp1&mtu.htm


Black screen when rdp over vpn Finally, We reduce MTU from 1500 to 1400 in the SonicWall. Then he can use RDC over VPN. Related Topics. How to change MTU ...
www.howtonetworking.com/casestudy/mtu1.htm



Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com
"Bill" <don't want any spam> wrote in message I have a Win2K workstation at one location. It is set up so I can VPN into
the box and once I an logged in, I can FTP through the tunnel to the IIS FTP
server set up there. I use CuteFTP to upload and download files when I
travel. Both sides are using a broadband connection.

I have three related problems.

1. Sometimes the FTP connection fails even though the VPN connection is
still connected.
2. In that case when I am uploading, the IIS FTP server is supposed to be
able to continue broken connections. I can see that the partial file remains
for a while. But if I try to resume I am told that the file cannot be opened
because some process is still accessing it. Eventually, FTP server deletes
it and I must start over.
3. Sometimes the VPN connection itself breaks for no apparent reason. Of
course the FTP client then fails it's upload. If I try to reconnect as soon
as I notice, sometimes I can't get in right away and sometimes I can. But
I'm rarely sure how much time passed between the connection breaking and
trying to reconnect it.

So, what might be causing these connections to break? I have guessed that
something in the protocol might be timing out. If that's a possibility, is
there any way to increase the timeouts, either through a dialog or the
registry? And is there any way to get IIS FTP server to keep the files so
they can be resumed?

Thanks...