TCP, UDP, and IP Packets




Linux Kernel



  • Automate a Linux Install
  • There is a single configuration file that answers all the setup questions that would pop up during a manual install.
  • Create a kickstart file (you can use /root/anaconda.ks as a template)
  • Boot the client machine with a cdrom or with a bootdisk(mkbootdisk))
  • KickStart File
    1. The ks.cfg file can be on a boot disk, network or on a cdrom.
    2. Commands Section (put LDAP server info here, grub password etc)
    3. Packages Section (mozilla, bind, sendmail, gimp etc)
    4. %Pre and %Post SEction (custom sections) You can disable services in the %Post section.
      Sample Boot command on client
      boot:linux ks=floppy
  • Apache
  • Dynamic Module Support (DSO)
  • Use the apsx tool build a a dynamic shared object (DSO).

  • Linux & Solaris Memory Tools
  • pmap : (-d) reports the memory map of a process, pstree(print process tree)
  • Solaris only : pmap,pflages (Print the /proc tracing flags), pldd ( List the dynamic libraries linked into each process,) ptree (print process tree)
  • Swap Files : You can create swap areas after a linux install on either a partition or a special file with the mkswap command.
  • mkswap /dev/hda4 (on a partion)
  • dd if=/dev/zero of=/swapfile bs=1024 count=65536 (create a empty file to use later as swap space)
  • mkswap /swapfile
  • swapon /swapfile or mount it in /etc/fstab.
  • Debugging with GDB
  • Typically when a kernel or process crashes, all you see are registers and stack information. (AKA OOPS :dump useful debugging information that can be used to diagnose the cause of problem,
  • gdb can do four main kinds of things to C & C++ Programs :
  • Start your program, specifying anything that might affect its behavior.
  • Make your program stop on specified conditions.
  • Examine what has happened, when your program has stopped.
  • Change things in your program, so you can experiment with correcting the effects of one bug and go on to learn about another.
  • type "gdb" to enter the debugger.
  • gdb process 1234 (debug a running process)
  • There is a newer tool LKST (requires a kernel patch and a recompile) captures process context switch, send signal, exception, memory allocation, send packet, etc." Unlike the GNU Debugger this is designed to run on a live system and can be useful in enterprise environments.
  • NIS+
  • Network Information Service. There is atleast one master, a slave and several clients. You create a db of common unix files you'd like to distribute (/etc/passwd, /etc/hosts etc) and run makedbm on the server to seed the database in binary format and use yppush to notify the slaves of changes. Nis ises /bin/portmap which is a server that converts RPC program numbers intp TCPIP protocol port numbers.
  • Client Programs:ypbind, ypwhich, ypcat, yppoll, ypmatch)
  • Server Programsypserv daemon
  • EEPROM Commands
  • printenv (prints out all eeprom paramters)
  • diag (diagnostics)
  • devalias (device aliases)
  • probe
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