RV120W Dropping File Transfers via SFTP

Unanswered Question

My problem seems to be a strange one. I have the RV120W running with port 22 forwarded to one of my servers. When attempting to upload a file from within my network via SFTP the file transfer starts and then quickly fails with the following error message. "Received disconnect from XXX.XXX.XXX.XXX: Packet corrupt. I have forwarded the port to different machines and the problem occurs no matter what machine I use. I see the same problem if I'm remote and try to download from my network. My point is that only outbound traffic is an issue. I have replaced the router with a linksys WRT and have also connected a PC directly to my cable modem and see no issues. The issue is only when I have the RV120W connected.

I have only had this router for a few weeks and the problem has occurred since I unboxed it.

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David Hornstein Fri, 07/23/2010 - 00:26
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Hi Rick,

I gotta get this right,  so I understand the desired behavior that you wish to see happen.

So, your  SFTP client PC is in your LAN  network with a private IP address, let me say

You are trying  from your SFTP client  to get to the SFTP server,  that may be at LAN IP address, by using the WAN IP address of the router as the destination address for your SFTP client.

You desire the RV120W router WAN IP interface to redirect that LAN clients request back into the LAN to the LAN based  SFTP server, via a Port forwarding function.


Is that the desired behavior?

Excuse the rough diagram below.  The red line is meant to show the logical flow of traffic that I think you desire.  The Blue lines represent LAN cable connection to the built in LAN managed switch.

So Like the diagram above, the red line indicates the logical desired traffic flow .

Or are you really trying from within the LAN going directly to the SFTP server at hypothetical address

Again, want to be really sure I truly understand the desired behavior ?

Do external client on the internet also have issues with file transfer to the LAN based SFTP server ?

I know you mentioned "only outbound traffic is an issue" but I wish to clarify what is the the desired behavior you want, so there is no ambiguity in my mind.

regards Dave


Thanks for the reply. I'm sorry I didn't get the issue explained well. I am using SFTP between my home network and my office network as well as a hosted server on the internet. Whether I am logged in at my office or whether I am using my hosted server I get the same issue. Any time that I have a SFTP transfer going outbound from my home network I see the issue. For instance, if I log into my hosted server and try to download a file from my home network I have the issue. If I upload a file to my home network from the same server I see no issue. And on the opposite, if I am home and try to upload a file to my hosted server it fails. If I download a file from the hosted server it works fine. I get the same results even when I use my laptop from a location outside my home network.

germaurice Thu, 07/29/2010 - 02:26
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I have the same problem which resides in using SSH connection and the error message is "Corrupted MAC on input.".

My feeling is when there is lot of trafic over the SSH connection, especially when transfering files, the error occurs. I got too the error when i had a lot of data printed on stdout of my SSH console. I led some tests without using the RV120W and i had no issues.

Here is the description of the both connection when the error occurs :

SSH Client ----- INTERNET ----- SDSL Router ----- RV120W ----- Switch ----- SSH Server

and reverted connection

SSH Client ----- Switch ----- RV120W ----- SDSL Router ----- INTERNET ----- SSH Server

The source of the problem, as seen on Internet, could be a network equipement, network cable, computer peripherals....

I hope my contribution could help you to find the source of the problem, which will be very helpful for me :)


germaurice Mon, 08/09/2010 - 08:32
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I would add some other information about this problem.

My collegues send email via IMAP/TLS connection over the 587 port.

Randomly, the connection broke up the uploading of the email.

I'm pretty sure there is a bug in the Cisco RV120W concerning SSL connections.

Firmware Version      
PID VID     RV120W-E V01

streaves Fri, 08/13/2010 - 15:55
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Hello Rick --Thanks for posting in the Support Community.

The RV 120W Engineering Team is reviewing your issue. Would you be kind enough to share your configuration file? This will help us troubleshoot.


Stephanie Reaves

Small Business Technology Group

streaves Tue, 08/24/2010 - 12:28
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Hi Rick -- Administration > Back/Restore Settings > Backup. By default, the file is named RV120W.cfg . You can attach it to a reply here or email it to me directly: streavesatciscodotcom.



streaves Wed, 08/25/2010 - 09:50
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Thanks, Rick. Good information. I've sent the file to engineering.

Stay tuned.



David Hornstein Sun, 08/22/2010 - 17:52
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Can you try the following to see if it works;

Goto Firewall -> Basic Settings -> Attack Checks page. Under LAN Security Checks menu,  disable Block UDP Flood option if not enabled already.

save your change

Observe if the WAN packets continue to drop.  It probably dropping DNS requests and killing web pages.

regards Dave

QuimaxWoods Fri, 08/27/2010 - 19:44
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I'm also going to be watching this thread closly to see if there is a resolution. I'm have the same issue with SSH connections.

habeebtc1980 Mon, 09/13/2010 - 10:08
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Additionally, for what it's worth, my layman's eye spots the CPU usage to always be pegged at between 95% and 100%.. 

My guess is that this has something to do with it.  Of course, I see no traffic to speak of that would cause this (I'm sniffing LAN-side via Wireshark).

Does anyone have any suggestions on what could be maxing the CPU?  And before you ask, NO I am NOT running any file sharing applications.  And Netstat -b on my client machine (currently the only one LAN-side) shows nothing as well.

habeebtc1980 Mon, 09/13/2010 - 10:09
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Does anyone have any recommendations on how I can debug the CPU being pegged?

Or, Cisco, can you comment on if there's a known issue here?

David Hornstein Mon, 09/13/2010 - 19:41
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Hi folks,

I rang the Small Business Support Center (SBSC) as I saw some of the same Issues as discussed in the above on my RV120W.

SBSC escalated my case to their next level support, i filled out a beta agreement  and got some beta code.

I must admit my RV120W is working much better.  Give them a call via the following URL.

Seems like you can get Beta code  to fix a lot of the issues discussed above.


Just ask the technician ,  to escalate the call so that you can get the beta code. (if you have any issue, refer the SBSC TAC technician to this posting)

I am hoping we will release non beta code very very shortly, but my router performance is looking much better.

I also unchecked Block UDP flood as it seemed to limit DNS requests, see my screen shots below;

regards Dave


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