Technology Insights

VSFTPD Error: GnuTLS error -9: A TLS packet with unexpected length was received.

I was tasked with configuring VSFTPD to allow SFTP or FTPES (FTP over explicit TLS/SSL) tonight for a client. The configuration already had regular FTP working which I verified using FileZilla as an FTP client. I was able to login and transfer files in both directions to and from the server. Next I verified that SFTP worked without issue and I was able to also transfer files in both directions using SFTP. For FTPES I had to make some changes and once I did make the changes I was still getting an error when attempting to do a directory listing using FileZilla. Below I describe the initial changes I made to vsftpd.conf, the errors I received attempting to connect with FTPES, and the way I resolved the problem.

Technology Insights

Use Wireshark And DD-WRT Router Firmware To Imitate Port Monitoring On A Router Switch Port

Earlier today I needed to find the quickest and easiest way to monitor all traffic to and from a specific device on my network. The goal was to see how much bandwidth based on a specific amount of time that the device was using. My initial hope was that I could configure port monitoring on my WRT54G running DD-WRT firmware however I quickly found out this is not an option. I eventually settled on adding a couple iptables commands that would send all traffic destined for or sourced from a specific IP address to another IP address. Follow the directions below to add the iptables commands to a router running DD-WRT firmware and then to capture the traffic on a computer running Wireshark.