Earlier I was setting up a PXE boot server that was connected to two networks and wanted to hand out DHCP addresses only on the second interface which in this case was eth1. The primary interface on the server is eth0 however that Ethernet port is attached to a switch that already has a DHCP server connected to it so I needed to make sure that the DHCP server only replies to requests on eth1. Use the dhcpd.conf configuration option below to specify the Ethernet interface that dhcpd will listen for and reply to DHCP and/or BOOTP requests.

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When attempting to install dhcp3-server on BackTrack Linux version 5 R3 you likely will run into a dependency error. This error was received on a brand new install of BT5r3 so the issue would be the same on any current install. Below I describe the error installing dhcp3-server on Backtrack in more detail as well as how to easily fix the problem. It should also be noted that this will likely fix other dependency issues you might have run into with a fresh install of BT5r3.

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Earlier while troubleshooting a possible issue with VMWare Player on Ubuntu Linux I needed to sniff broadcast traffic. The goal was to see if there were multiple MAC addresses sending out broadcast traffic after VMWare Player was installed on Ubuntu even without a VM actually running. Below is a quick example of how to sniff Ethernet broadcast and multicast traffic using tcpdump.

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Earlier a friend called me while working at a client location and needed to know how to configure the VLAN on a Cisco 7940 IP Phone. I always forget the different ways to unlock different phones and wasn’t having an easy time locating the method on Google but finally did locate how to unlock the the Cisco 7940. Below is information on how to unlock the Cisco 7940 phones.

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While working on various things in a Asterisk VoIP deployment earlier I needed to override the DHCP NTP settings for a specific phone because this particular user was remote. The configuration file for their phone was actually using a different outbound proxy and SIP registration server address so they could operate remotely. One of the issues pointed out to me was the fact that the phone’s time was never correct and after some basic investigation I was able to locate the issue which is described below as well as how to override the DHCP NTP address settings via the Polycom SountPoint CFG (configuration) files.

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