[Dnsmasq-discuss] dnsmasq difficulty

Aaron D. Brooks aaron.brooks at sicortex.com
Thu Mar 6 04:47:57 GMT 2008

If the package "lsof" is installed on your system you can run the
following command as root to show if any services (Avahi, perhaps) are
sitting on the ports that dnsmasq may want to use (depending on your
configuration). I include all three ports that dnsmasq serves.

    # lsof -i :domain -i :bootps -i :tftp
    dnsmasq 7734 nobody    5u  IPv4  13664       UDP *:bootps 
    dnsmasq 7734 nobody    6u  IPv4  13673       UDP *:domain 
    dnsmasq 7734 nobody    7u  IPv4  13674       TCP *:domain (LISTEN)
    dnsmasq 7734 nobody    8u  IPv6  13675       UDP *:domain 
    dnsmasq 7734 nobody    9u  IPv6  13676       TCP *:domain (LISTEN)
    dnsmasq 7734 nobody   10u  IPv4  13677       UDP *:tftp

Note that in my configuration has dnsmasq bound to the above ports. Depending
on how Etch sets up logging you may have log information in /var/log/messages
or some other log file which might give you a more specific error message. (I
don't recall if dnsmasq is any clearer in the log files on this topic.)

Hope that helps,


On Wed, Mar 05, 2008 at 04:05:57PM -0800, L Forrister wrote:
> Hi
> I have just begun trying to configure dnsmasq, and am encountering a 
> problem.  I am also really new to Debian, so please bear with me.
> I'm running Debian Etch.  The package manager installation of dnsmasq 
> v2.35-1 went fine. But it doesn't start at boot up.  Running it manually 
> in a root shell I'm getting the message
> < dnsmasq: failed to create listening socket: Address already in use >
> There's no other dns or dhcp daemons running, so I have no idea what 
> socket/address the message is referring to and even less which software 
> is creating the conflict. 
> Help!
> Thanks
> ~~LF

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