Secure Shell
Question about SCP stalling over VPN Mar 09 2010 05:44PM
Matthew Case (mattcase specializedbusinesssoftware com) (2 replies)
RE: Question about SCP stalling over VPN Mar 12 2010 06:08PM
Robin, Robin (robinr muohio edu)
Re: Question about SCP stalling over VPN Mar 10 2010 03:04AM
Darren Tucker (dtucker zip com au) (1 replies)
Re: Question about SCP stalling over VPN Mar 12 2010 08:41AM
John Morrison (john morrison101 googlemail com) (1 replies)
Re: Question about SCP stalling over VPN Mar 12 2010 02:13PM
Matthew Case (mattcase specializedbusinesssoftware com) (2 replies)
Re: Question about SCP stalling over VPN Mar 22 2010 05:02PM
Dennis Nezic (dennisn dennisn dyndns org) (1 replies)
I have run into a similar problem, although I don't get any "rcvd
adjust" debug messages -- instead my scp transfers stall -- at a pretty
predictable place too (not exactly, but to within a few megabytes). My
problem ONLY started after I upgraded my kernel (and maybe some other
things :s, from 2.6.19 to 2.6.33). My NFS transfers also started
"stalling", for many minutes (5-15min usually), although they are
retried, and eventually finish. Again, I don't think ANY of these
problems ever happened with my old kernel for a couple years.

During the stalls, netstat says the tcp connection is still
ESTABLISHED, and when I Ctrl-C the stalled scp transfer, the sshd
server logs a "Received disconnect" message. No other debug messages
are shown for me. I'll try to get a tcpdump.

On Fri, 12 Mar 2010 09:13:47 -0500, Matthew Case wrote:
> First and foremost, thank you to everyone for your responses. I
> checked the MTU on both sides and it's currently 1500 so I'm assuming
> it's not a mismatch. My VPN is a pair of old Netscreen 5xp boxes, and
> I can't find anything relating to MTU or packet size in the
> configuration, but I'm still looking.
>
> Secondly, to answer your question John, There is no persistent
> connection between the servers. I could feasibly set up an NFS share
> between the two but I have a sneaking suspicion that if the problem
> is some sort of packet mangling by the VPN during file transfers, the
> actual mechanism used to transfer the file will be irrelevant.
> However, I will set this up and test it and report back my results,
> most likely next Monday.
>
> On 3/12/2010 3:41 AM, John Morrison wrote:
> > Matt,
> >
> > If you are using ssh do you need to use scp as well? Or is just
> > plain copy ok?
> >
> > On 10 March 2010 03:04, Darren Tucker<dtucker (at) zip.com (dot) au [email concealed]> wrote:
> >
> >> Matthew Case wrote:
> >> [...]
> >>
> >>> I've looked high and low and haven't really come up with anything
> >>> definitive. Someone somewhere had mentioned fiddling with MTU
> >>> settings, but I'm not really sure what that will accomplish as I
> >>> am unfamiliar with what MTU is and does. If this question has
> >>> been answered previously, I apologize ahead of time. Thanks!
> >>>
> >> This does sound like the MTU problem to which you refer. See
> >> http://www.snailbook.com/faq/mtu-mismatch.auto.html for details.
> >>

[ reply ]
Re: Question about SCP stalling over VPN Mar 24 2010 01:23AM
Dennis Nezic (dennisn dennisn dyndns org) (1 replies)
Re: Question about SCP stalling over VPN Mar 24 2010 08:10PM
Dennis Nezic (dennisn dennisn dyndns org)
RE: Question about SCP stalling over VPN Mar 12 2010 06:03PM
Paul Ryland (paul transversal com)


 

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