IIS 5 & IIS 6
Troubleshooting FTP 426 Errors (Connection closed; transfer aborted)
Last post May 07, 2007 08:07 AM by ShawnSmiley
May 02, 2007 08:49 AM|ShawnSmiley|LINK
We have a system that has approximately 30 kiosks out in the field that connect in to our central FTP server each night to download software and content updates. For the most part this system has been working pretty reliably. However we do have periodic
cases where the kiosks fail to download updates with the kiosks reporting that the connect was closed by the remote host and the FTP Logs on the server showing 426 status codes.
At first I was just ignoring the errors assuming it was some kind of random network connectivity problem since typically only 1-5 of the 30 kiosks tend to encounter the problem. However, I started noticing a pattern where the error most frequently occurred
while downloading one specific file (probably about 75% of the errors). The errors also do not consistently occur from any specific kiosks or physical locations.
So my question is, what sort of things can cause a FTP 426 error and are there any recommendations or best practices that we can follow to reduce or eliminate their occurrences?
Here is some information on our system setup:
The server is a Windows 2003 Standard Edition Server running IIS 6 for both website hosting and FTP.
The kiosks are Windows XP Pro all-in-one touchscreen units that connect to a Linksys Wireless Router using 802.11g with WPA Encryption. The updater application is a .net 2.0/3.0 app that uses a WCF call to download a list of updated files and then uses
the System.Net.WebClient class to download the updates.
May 02, 2007 11:01 PM|ganeshanekar|LINK
Here are few KBs from MS which talks about this but this may or may apply in your situation.
306183 Repeated 426 Entries in the IIS FTP Log
318380 IIS Status Codes
817829 FIX: Passive Mode FTP May Break with Multiple IP Addresses on External Interface
283679 Information About the IIS File Transmission Protocol (FTP) Service
If you have already identified the file name, did you try to rename the file? BTW what is the size of that file?
Also what client are you using to download files from FTP server? IE or someother?
What FTP mode are using? Can you check maxbandwidth property in IIS Metabase?
May 03, 2007 08:19 AM|ShawnSmiley|LINK
Thank you for the links and the suggestion to check the IIS Metabase. I'll look into them this morning.
The file that we typically have trouble downloading is about 3.5 MB named "k.exe". Unfortunately renaming the file isn't an option since this is the primary presentation executable for our kiosks and renaming the file would require a number of manual changes
to the kiosks.
The downloads are being done by a .net 2.0 Windows Service using the WebClient class that is built into the .net framework. I need to check the docs to see if it defaults to passive or active connections when doing FTP Downloads. This service downloads
files ranging in size from 1KB to about 75 MB and there are approximately 1000 files in the distribution though the service only downloads the individual files that have been modified since the last update.
May 07, 2007 08:07 AM|ShawnSmiley|LINK
Thanks again for your suggestions.
The problem ended up being completely unrelated to IIS. The firewalls at a couple locations were doing virus scanning on file download requests and blocking this one file.
We updated the firewall rules to allow the download from our server and everything is working perfectly now.