Tag - centos

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Monday, July 29 2013

Useful Null Routes

On every router, there are certain routes that are useful to install to prevent leakage of invalid traffic related to private address space.

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Friday, April 26 2013

Prepare RedHat / CentOS for Cloning

To prepare a RHEL/CentOS/etc host for cloning (eg, duplicating a Virtual Machine or creating a VM Template), use the following commands as the last steps:

touch /.unconfigured
rm -f /etc/ssh/ssh_host_*
ifdown eth0
sed -i '/^HWADDR=.*$/d' /etc/sysconfig/network-scripts/ifcfg-eth0
ifup eth0
rm -f /etc/udev/rules.d/70-persistent-net.rules
shutdown -h now

Source: https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Virtualization/3.0/html/Evaluation_Guide/Evaluation_Guide-Create_RHEL_Template.html

Saturday, May 26 2012

Installing ipset on CentOS 6

I assume this will work on RedHat 6 too:

# yum install http://people.redhat.com/twoerner/BZ/477115/ipset-6.7-2.el6.x86_64.rpm http://people.redhat.com/twoerner/BZ/477115/libmnl-1.0.1-1.el6.x86_64.rpm http://people.redhat.com/twoerner/BZ/477115/libmnl-devel-1.0.1-1.el6.x86_64.rpm

Yes, you can copy and paste.

Note that this isn't adding any repositories, so I'm not sure what impact this will have in future since the packages won't get automatically updated by `yum update` (security updates, breakage when kernel updates etc?)

Thursday, February 10 2011

Native IPv6 with Internode and CentOS

This is a WIP. Notes so far.

At the moment, this results in an error from DHCPv6 Client when trying to assign an addrss to ppp200:

Feb 10 23:28:50 tank dhcp6c[1063]: transmit failed: Network is unreachable

Manually adding an address makes it work:

Feb 10 23:28:47 tank dhcp6c[1382]: request prefix is 2001:44b8:7206:d180::/60
# ip -6 a a 2001:44b8:7206:d180::1/48 dev ppp200
# ping6 2001:44b8:1::6
PING 2001:44b8:1::6(2001:44b8:1::6) 56 data bytes
64 bytes from 2001:44b8:1::6: icmp_seq=0 ttl=59 time=27.8 ms
64 bytes from 2001:44b8:1::6: icmp_seq=1 ttl=59 time=27.3 ms
64 bytes from 2001:44b8:1::6: icmp_seq=2 ttl=59 time=27.6 ms

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