dnsmasq

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computing: software: dnsmasq

Overview

dnsmasq is a domain name resolver for Linux. It provides DNS forwarding and DHCP.

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Files

• /var/lib/misc/dnsmasq.leases

Related Pages

• dnsmasq manpage
• dnsmasq.conf
  • dnsmasq.conf sample

Links

Reference

• Wikipedia
• official home page
  • manpage for latest version

Technical Articles

• 2004-07-06 In a DNS bind? Get Out with dnsmasq
• 2005-04-04 Dnsmasq: Poisoning and Denial of Service vulnerabilities at gentoo.org (applies only to older versions)

Notes on making dnsmasq actually work

• Don't accidentally run dhclient. If you do, you'll need to recreate the resolv.conf file. Fortunately, this is pretty simple; it's just a few lines in this format:

nameserver ip address

...where the list of IP addresses (one per line) can be found in the dnsmasq upstream servers file you created earlier. (You did, right?)

• There are a number of other related files which need to be set up right, but they've gone out of my head for the moment so I'll have to come back to this.

• The dnsmasq server needs to have a static IP address. It will work without one – until the lease expires, and then the server won't have any IP address, and nobody will be able to do DNS or DHCP.
• The dnsmasq server also needs to know the IP address of the gateway router (most commonly 192.168.0.1).
• In Kubuntu, both of these can be set via the System Settings app, in "network settings".

dnsmasq and Vonage

VoIP phone adapters from Vonage (and presumably other VoIP services) work fine with dnsmasq if all is well with dnsmasq. The one problem I encountered was when I had been trying to set up dnsmasq on another box ("rizzo") and it wasn't quite working right, and then later unbeknownst to me it had somehow gotten started up again (probably during a reboot) and was providing DHCP for the Vonage boxes (instead of the working dnsmasq that was supposed to be doing so) – which resulted in a lack of dial-tone. The tipoff was when I checked the dnsmasq.leases file and it only had one line in it, for a MAC ID matching the other Vonage box which I had been able to get to work. Turned off the broken dnsmasq, powered off/on the non-working Vonage box, and about a minute later I had dial tone. --Woozle 15:08, 25 December 2006 (EST)

Update: this happened again, and it was only after an email exchange with Vonage that I thought to check into rizzo's dnsmasq.leases file again – and there was the Vonage box's MAC ID. Kudos to Vonage for giving me enough technical information to point me in the right direction. (I guess I should just uninstall dnsmasq from rizzo until I have time to really tackle it and figure out why it isn't working.) --Woozle 14:36, 14 February 2007 (EST)