[Dnsmasq-discuss] dnsmasq on Ubuntu 14.04 and Network Manager

[Brian Watson]

Hi,
I had this working on Ubuntu 10.04, but now I would like to get it
working on 14.04 with a better understanding of what's happening. On 10.04
I installed dnsmasq without understanding that there was probably one
already installed as part of NetworkManager. With 14.04 I would like to
just use the version that's used by NetworkManager, but I didn't understand
the following:

1. The first thing I needed to do was to find the existing dnsmasq.conf so
that I could add my changes there and there is a version in
/etc/dbus-1/system.d/dnsmasq.conf
2. dnsmasq.conf - it has XML type data in it related to busconfig with
some policies depending on the user.
3. Can this file be modified so that I can add an interface with an
address range of IP addresses that I would like to use?
4. If I install an independent version of dnsmasq does that interfere with
the NetworkManager one?
5. Where is the NetworkManager one being started from? I looked in
/etc/init.d, but I didn't see anything for dnsmasq. I grepped the running
processes and it shows up as running.

Best Regards,
BW

[Dan Williams]

Post by Brian Watson
Hi,
I had this working on Ubuntu 10.04, but now I would like to get it
working on 14.04 with a better understanding of what's happening. On 10.04
I installed dnsmasq without understanding that there was probably one
already installed as part of NetworkManager. With 14.04 I would like to
just use the version that's used by NetworkManager, but I didn't understand

NM doesn't use a private on-disk copy of dnsmasq or anything, it uses
the normal system copy that's already installed. But it spawns a
private *runtime* dnsmasq process to handle either (a) the local caching
nameserver functionality, or (b) the internet connection sharing
functionality.

So it depends on what you want to use dnsmasq for; which one are you
trying to do? If it's internet connection sharing, then with the NM
0.9.8 in Ubuntu 14.04 you cannot change the address range handed to
clients on the interface. That has been fixed in NM 0.9.10 and later
but even though that version is more than a year old, it is only
included in Ubuntu 15.04.

Typically you never really need to touch the dnsmasq that NM spawns,
because modifications are usually done through the NM configuration not
dnsmasq. An independently installed and configured dnsmasq usually does
not conflict with NetworkManager's copy, unless:

1) you have configured the independent copy to bind to the same
interface/IP address that NetworkManager's copy is bound to, or you have
allowed the independent copy to bind to all interfaces ("*") which
obviously conflicts with the one NM spawns for interfaces it manages

2) you have enabled NM's local caching nameserver functionality and you
have configured the independent copy to do the same thing

In Ubuntu, NM and dnsmasq communicate via D-Bus, not through
configuration files. For internet connection sharing, NM spawns and
kills its own copy for that specific interface. For local caching DNS,
I think the dnsmasq may be started by

Dan

Post by Brian Watson
1. The first thing I needed to do was to find the existing dnsmasq.conf so
that I could add my changes there and there is a version in
/etc/dbus-1/system.d/dnsmasq.conf
2. dnsmasq.conf - it has XML type data in it related to busconfig with
some policies depending on the user.
3. Can this file be modified so that I can add an interface with an
address range of IP addresses that I would like to use?
4. If I install an independent version of dnsmasq does that interfere with
the NetworkManager one?
5. Where is the NetworkManager one being started from? I looked in
/etc/init.d, but I didn't see anything for dnsmasq. I grepped the running
processes and it shows up as running.
Best Regards,
BW
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http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss

[Brian Watson]

Thanks! I went ahead and installed an independent copy and everything works
fine. I only needed it for dhcp functionality.

Post by Brian Watson

Post by Brian Watson
Hi,
I had this working on Ubuntu 10.04, but now I would like to get it
working on 14.04 with a better understanding of what's happening. On

10.04

Post by Brian Watson
I installed dnsmasq without understanding that there was probably one
already installed as part of NetworkManager. With 14.04 I would like to
just use the version that's used by NetworkManager, but I didn't

understand
NM doesn't use a private on-disk copy of dnsmasq or anything, it uses
the normal system copy that's already installed. But it spawns a
private *runtime* dnsmasq process to handle either (a) the local caching
nameserver functionality, or (b) the internet connection sharing
functionality.
So it depends on what you want to use dnsmasq for; which one are you
trying to do? If it's internet connection sharing, then with the NM
0.9.8 in Ubuntu 14.04 you cannot change the address range handed to
clients on the interface. That has been fixed in NM 0.9.10 and later
but even though that version is more than a year old, it is only
included in Ubuntu 15.04.
Typically you never really need to touch the dnsmasq that NM spawns,
because modifications are usually done through the NM configuration not
dnsmasq. An independently installed and configured dnsmasq usually does
1) you have configured the independent copy to bind to the same
interface/IP address that NetworkManager's copy is bound to, or you have
allowed the independent copy to bind to all interfaces ("*") which
obviously conflicts with the one NM spawns for interfaces it manages
2) you have enabled NM's local caching nameserver functionality and you
have configured the independent copy to do the same thing
In Ubuntu, NM and dnsmasq communicate via D-Bus, not through
configuration files. For internet connection sharing, NM spawns and
kills its own copy for that specific interface. For local caching DNS,
I think the dnsmasq may be started by
Dan

Post by Brian Watson
1. The first thing I needed to do was to find the existing dnsmasq.conf

so

Post by Brian Watson
that I could add my changes there and there is a version in
/etc/dbus-1/system.d/dnsmasq.conf
2. dnsmasq.conf - it has XML type data in it related to busconfig with
some policies depending on the user.
3. Can this file be modified so that I can add an interface with an
address range of IP addresses that I would like to use?
4. If I install an independent version of dnsmasq does that interfere

with

Post by Brian Watson
the NetworkManager one?
5. Where is the NetworkManager one being started from? I looked in
/etc/init.d, but I didn't see anything for dnsmasq. I grepped the running
processes and it shows up as running.
Best Regards,
BW
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Dnsmasq-discuss mailing list
http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss