Archive for September, 2007

Setting up a BizHub420 in UNIX 

I had to setup a Minolta BizHub 420 multifunction device on SUN Solaris 9 (UNIX), this is how I did it (of course, from the command line): Download the Linux driver for the printer from here. Install the driver (PPD file) by copying the file (KO500UX.ppd) to /usr/share/cups/model/, then restart CUPS: cp KO500UX.ppd /usr/share/cups/model/ /etc/init.d/cups […]

Create a self-signed SSL cert for 20 years! 

I was thinking, if you are making your own cert for internal use or testing, why make it for only a year? Here’s how to make one that won’t expire for twenty years… Generate a key: openssl genrsa -des3 -out test.key 1024 Remove the passphrase: cp test.key test.key.orig openssl rsa -in test.key.orig -out test.key Create […]

Reduce ability of a DOS on Linux 

To change the settings quickly run the following from the command line and the restart networking: echo 30 > /proc/sys/net/ipv4/tcp_fin_timeout echo 1800 > /proc/sys/net/ipv4/tcp_keepalive_time echo 0 > /proc/sys/net/ipv4/tcp_window_scaling echo 0 > /proc/sys/net/ipv4/tcp_sack Or change them in /etc/sysctl.conf for permanence after a reboot: net.ipv4.tcp_fin_timeout = 30 net.ipv4.tcp_keepalive_time = 1800 net.ipv4.tcp_window_scaling = 0 net.ipv4.tcp_sack = 0

Netstat Connection Status 

* CLOSED: The socket is not in use. * LISTEN: The socket is listening for incoming connections. * SYN_SENT: The socket is actively trying to establish a connection to a remote peer. * SYN_RCVD: The socket has passively received a connection request from a remote peer. * ESTABLISHED: The socket has an established connection between […]