Linux

IP address change notifier script

This is a simple bash script that is run by crontab every 5 minutes on a linux box. It e-mails me the new address when a change of IP address is detected. The script (ipchangemail.sh) #!/bin/bash # Check if IP-address has changed. If a change has occured, mail me the new address # Add the […]

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Network

Network upgrade Ubuntu Server 8.04 to 8.10

This post describes how I upgraded my Ubuntu (Hardy Heron) 8.04 server installation to (Intrepid Ibex) 8.10 from the command line. First you’ll need to make sure you are running the latest packages # sudo aptitude update # sudo aptitude safe-upgrade Then you will need to install the Ubuntu upgrade package # sudo aptitude install […]

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Network

Disable IPv6 on Redhat RHEL4

First you remove this line from /etc/modprobe.conf if this line exists. alias net-pf-10 ipv6 Add the following line to /etc/modprobe.conf alias net-pf-10 off Reboot the system. IPv6 is now disabled. To re-enable IPv6, remove the alias net-pf-10 off line from /etc/modprobe.conf and reboot the machine. I’ve also made a post about how to disable IPv6 […]

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Network

Listen to network traffic using tcpdump

Please note that you have to be the root user to use this command because it puts the network card in promiscuous mode. # tcpdump -i eth0 -A -s 0 udp port 1514 and host 192.168.0.1 The example above command listens on port 1514 which is the port ossec-hids uses on its secure communication between […]

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Network

Disable IPv6 on Redhat RHEL5

This post describes how to disable IPv6 on a Redhat (RHEL5) installation. I haven’t had the time to test it on other version of Redhat. Edit /etc/sysconfig/network and change NETWORKING_IPV6=no Edit /etc/modprobe.conf and add these lines alias net-pf-10 off alias ipv6 off Stop the ipv6tables service # service ip6tables stop Disable the ipv6tables service # […]

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