On Sat, Jul 22, 2006 at 06:37:46AM -0700, Ken Herron wrote: > Marc Elliot Hall wrote: > >On Fri, Jul 21, 2006 at 08:50:46AM -0700, Ken Herron wrote: > > > >>Ken Herron wrote: > >>Okay, see <http://www.ncftp.com/ncftpd/doc/misc/ftp_and_firewalls.html>, > >>in particular "Why PORT Poses Problems for Routing Devices" and > >>"Problems when the FTP Server is Listening on a Non-Standard Port > >>Number". Now imagine your netgear thinks it's dealing with FTP and is > >>doing that to your ssh sessions. > >> > >Not that I'm disagreeing with you about the router's possible confusion, > >but I'm not running an FTP server. ;-) > > I never said you were. You're running ssh over port 21, which is > normally the ftp command channel port. So the router might be applying > its ftp forwarding support to your ssh traffic and scrambling it in the > process. > > >I'll investigate further in this direction; however I don't think my > >appliance is nearly smart enough to rewrite packet headers. It just > >accepts inbound traffic on designated ports and passes it through > >unmodified to the same port on a specified host on my network. > > Netgear routers can port-forward ftp. If you'd read the link above, > you'll see that dumb packet forwarding isn't sufficient to port-forward > ftp. So netgear routers almost certainly have logic to do the protocol > monitoring and packet rewriting described.
Thank you for the additional comments, Ken. I have read the link you referenced, and agree that there is a possible relationship between the issue I'm experiencing and the Netgear WGT624's firmware thinking that if an incoming packet is hitting port 21, it must therefore be FTP - not that that would be "normal" given my last 18-odd months of successful ssh-ing with the same config. However, I have concluded that this broken behavior is indicative of a hardware failure (Cosmic rays? Overheating? Whatever...), because while tinkering with various PuTTY settings while troubleshooting (frex, enabling and disabling single-DES in SSH-2, deleting the saved rsa key, etc.), I got this PuTTY Fatal Error: ++++++ Server sent disconnect message" type 2 (SSH_DISCONNECT_PROTOCOL_ERROR) Corrupted MAC on input ++++++ and that led me here: http://www.derkeiler.com/Newsgroups/comp.security.ssh/2005-03/0113.html I'm going to attempt to update the firmware to 4.2.11; but if that doesn't fix things, I'll have to get me a new device (OpenWrt doesn't have a Free replacement available yet). -- Marc Elliot Hall www.hallmarc.net _______________________________________________ vox-tech mailing list [email protected] http://lists.lugod.org/mailman/listinfo/vox-tech
