Disable ipv6 on RHEL5

Found a post that explained what was needed to disable ipv6 on our installation of RHEL5.

The only thing that we really need is to add a line in /etc/modprobe.conf

alias net-pf-10 ipv6 off

Simple enough!



Bonding NICs in RHEL5

We started testing some NIC bonding on our RHEL 5 VM and we will be testing on real hardware soon. The ultimate goal is to add this setup in our kickstart file.

We created these files for testing:



Added these lines to /etc/sysconfig/network-scripts/ifcfg-eth0 and ifcfg-eth1:


in /etc/modprobe.conf we added these lines:

alias bond0 bonding
options bond0 miimon=100 mode=1

We just need to test on some physical servers and see how all this works now.


Rebuilding the DVD ISO for CentOS 5 or RHEL 5

I found a few documents on the Internet about what I needed to do to rebuild the DVD to integrate my kickstart file. Unfortunately none of the solution had all the needed command in one place for my setup to work so here is my cookbook from the different sources.

First I mounted the dvdrom with the CentOS DVD to /mnt/cdrom:

mount /dev/cdrom /mnt/cdrom

Then I copied a few files:

  • cd /tmp
  • cp -R /mnt/cdrom/isolinux ./
  • cp -R /mnt/cdrom/CentOS ./isolinux/
  • cp -R /mnt/cdrom/* ./isolinux/ [say yes to overwrite the TRANS.TBL]
  • cp -R /mnt/cdrom/.discinfo ./isolinux/
  • cp ks.cfg /tmp/isolinux/

For my RHEL5.1 rebuild I did similar commands but the paths are a bit different:

  • cd /tmp
  • cp -R /mnt/cdrom/isolinux ./
  • cp -R /mnt/cdrom/Server ./isolinux/
  • cp -R /mnt/cdrom/VT ./isolinux/
  • cp -R /mnt/cdrom/images ./isolinux/
  • cp -R /mnt/cdrom/Cluster ./isolinux/
  • cp -R /mnt/cdrom/ClusterStorage ./isolinux/
  • cp /mnt/cdrom/* ./isolinux/ [say yes to overwrite the TRANS.TBL]
  • cp -R /mnt/cdrom/.discinfo ./isolinux/
  • cp ks.cfg /tmp/isolinux/

I had to change permissions on 2 files:

  • chmod 664 ./isolinux/isolinux.bin
  • chmod 664 ./isolinux/isolinux.cfg

I had to edit the isolinux.cfg (in the isolinux directory) to change a couple of lines:

  • the “default linux” line became “default ks
  • The 2 line after “label ks” went from “append ks initrd=initrd.img” to “append ks=cdrom:/ks.cfg initrd=initrd.img

The isolinux.cfg file now looks like:

default ks
prompt 1
timeout 600
display boot.msg
F1 boot.msg
F2 options.msg
F3 general.msg
F4 param.msg
F5 rescue.msg
label linux
kernel vmlinuz
append initrd=initrd.img
label text
kernel vmlinuz
append initrd=initrd.img text
label ks
kernel vmlinuz
append ks=cdrom:/ks.cfg initrd=initrd.img
label local
localboot 1
label memtest86
kernel memtest
append -

To build the ISO (all this on one line):

mkisofs -o centos5-dvd1.iso -b isolinux.bin -c boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -r -R -J -V “CentOS 5.1 (CentOS) Disk1” -A “CentOS 5.1 (CentOS) Disk1” -p “Cinq” -T isolinux/

For Red Hat Entreprise Linux 5.1 I had to change the label for the DVD from “CentOS 5.1 (CentOS) Disk1” to “RHEL_5.1 x86_64 DVD” (obviously I am using the x64 version for RHEL5) so the command became:

mkisofs -o centos5-dvd1.iso -b isolinux.bin -c boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -r -R -J -V “RHEL_5.1 x86_64 DVD” -A “RHEL_5.1 x86_64 DVD” -p “Cinq” -T isolinux/

Reference sites:


This piece of software seems quite promising to solve some of the issues that I have on my desk. I would like different computer to integrate a bit better and the main 2 features promise just that: software kvm and shared clipboard. I will have to test Synergy on my main Linux desktop with either my Mac and the Windows laptop or maybe a second Linux desktop. I need more screen space on my desk.