On one of my RHEL5 boxes, there where a couple of services that were allergic to IPv6. Hence I had to disable the IPv6 service, here is a rough how-to:
To disable IPv6 we have to do three things:
1) Disable the IPv6 kernel module
2) Remove / Disable IPv6 related network configuration entries.
3) Turn off IPv6-only services.
To disable kernel module, add following lines to /etc/modprobe.conf
alias net-pf-10 off
options ipv6 disable=1
Now remove ipv6 entries from network configuration file /etc/sysconfig/network
Change the setting NETWORKING_IPV6=yes
to NETWORKING_IPV6=no
Also, remove any other IPv6 related settings you might find here. Most probable ones are:
IPV6_DEFAULTGW and IPV6_AUTOCONF
In addition you can also turn off ipv6 per Ethernet interface. But in my experience, this is optional.
Go to /etc/sysconfig/network-scripts
Find if any interface have ipv6 turned on
grep -i ipv6 ifcfg*
If enabled, you will find following entries in the ifcfg-INTERFACE files.
IPV6INIT=yes
IPV6ADDR=YOUR_IPv6_IP_HERE
Remove those entries.
Now disable any dedicated ipv6 based service. Currently the only only ipv6 exclusive service I am aware of is iptable for ipv6 ( called ip6tables ). Turn that off.
service ip6tables stop
chkconfig ip6table off
All set, reboot the host and it will come up with ipv6 turned off.
reboot
