I've been using a Knoppix CD to boot a workstation and configure it as a DHCP and TFTP server for use as a PXE boot server. (I use it to boot a modified copy of the Novell ZenWorks for Desktops Imaging system, which is itself a very small Linux system with their imaging program included.)

I've been using Knoppix 3.3, and it worked fine as of the 2003-11-19 ISOs. When I tried to upgrade my Knoppix CD to the 2004-02-09 ISO, I found that I had lost the ability to TFTP. I'm using the same scripts as I was using on 2003-11-19, and I see in.tftpd loaded ("in.tftpd -c -l -s /tftp"). I can TFTP to the server on localhost; that much works fine. What I cannot do any more is TFTP to anything other than localhost.

If, for example, the Knoppix workstation is currently 10.10.10.10, I can TFTP to localhost (obviously both "localhost" or 127.0.0.1 work), but I cannot TFTP to 10.10.10.10 from the local workstation nor from any other workstation. It works with 2003-11-19, but it "just doesn't work" with 2004-02-09.

The only thing I see in the changelog for 2004-02-09 is "fixed Knoppix-Terminalserver problem with new libacl"... wait a minute...
I should've known... with the new ISO, I needed to edit /etc/hosts.allow to allow tftp. A bit of source reading in /usr/sbin/knoppix-terminalserver was enough to tell me that adding a line something like "tftp in.tftpd : ALL@ALL : ALLOW" to the /etc/hosts.allow would be enough to shove it wide open (feel free to open it less wide if you're not reimaging the entire network ). I'm better now, but just in case anyone else was trying to figure this one out, I'll post this anyway.