[Dnsmasq-discuss] dnsmasq is offering ip from different pool

[shashikumar Shashi]

Hi,

“

*Acknowledge on "Client moves".*  *The 'releases IP' is probably*

*something like "I'm unaware that IP stands for Internet Protocol*

*and want to try how far I can get by being vague how the release*

*of the DHCP lease was done"*

—>

Client is executing “dhclient -4 eth1 -r” to release the IP address.





*The issue of moving clients,*

*the issue of interfaces go down and come up,*

*the issue of moving clients AND flipping interfaces?*

—>

There is no flapping of the interfaces, interfaces are not going down and
comping up. Need to have at least one interface in DOWN state with dhcpv4
pool address range defined for it, to reproduce the issue.



The steps to reproduce the issue are as follows:

1) Have one client, 3 dhcp pools for 3 vlans or interfaces as shown below.
Out of these 3 interfaces, need to keep one interface in DOWN state, and
move the client across the other two UP interfaces, to reproduce the issue.

vlan9 (State UP) : Range: 192.168.9.10-192.168.9.254

vlan19 (State UP): Range: 192.168.19.10-192.168.19.254

vlan99 (State DOWN): Range: 192.168.99.10-192.168.99.254



2) Put the client on vlan9. Client gets IP from vlan9 pool (e.g.
192.168.9.10) by executing “dhclient -4 eth1”.



3) Put the same client on vlan19. Client releases previously acquired IP
(e.g. 192.168.9.10) by executing “dhclient -4 eth1 -r”.



4) The same client tries to get the IP by executing “dhclient -4 eth1”.

Here client should get IP address from 192.168.19.xx pool, but it gets from
192.168.99.xx pool.



5) In case if the issue is not seen at step 4, then need to move the client
across vlan9 and vlan19 couple of times, where client will release the
previously acquired IP address on the current vlan and then try to acquire
the IP address on the current vlan.



Looking for your help to root cause the issue.

”





Thanks and Regards,

Shashi

On Sun, Aug 6, 2023 at 2:01 PM Nym <stappers at stappers.nl> wrote:

> On Sun, Aug 06, 2023 at 01:24:02AM +0300, 0zl wrote:
> > On 8/4/23 09:24, shashikumar Shashi wrote:
> > > Hi,
> > >
> > > Observing that dnsmasq is offering DHCP IP to the client
> } } Observing that dnsmasq is offering DHCP IP-address to the client
> > > from a vlan pool which is in DOWN state.
> > >
> > > E.g. If there are 3 dhcp pools
> > >
> > > vlan9 (State UP) : Range: 192.168.9.1-192.168.9.254
> > > vlan19 (State UP): Range: 192.168.19.1-192.168.19.254
> > > vlan99 (State DOWN): Range: 192.168.99.1-192.168.99.254
> > >
> > > 1) Client on vlan9 gets IP from vlan9 pool
> > > 2) Client moves to vlan19, releases IP
>
> Acknowledge on "Client moves".  The 'releases IP' is probably
> something like "I'm unaware that IP stands for Internet Protocol
> and want to try how far I can get by being vague how the release
> of the DHCP lease was done"
>
>
> > > 3) Client on vlan19 requests IP --> dnsmasq offers IP 192.168.99.xx
> from
> > >    vlan99 pool (incorrect pool), instead of vlan19 pool.
> > >
> > > If the vlan99 is in UP state, then dnsmasq offers the IP from the
> vlan19
> > > pool (the correct pool).
> > >
> > > Has anyone come across such an issue?
> > >
> > I've encountered this issue as well,
>
> The issue of moving clients,
> the issue of interfaces go down and come up,
> the issue of moving clients AND flipping interfaces?
>
>
> > I ended up working around it by creating bridges that have those vlans
> > as their bridge port. This way the bridge stays up to dnsmasq even
> > when I take one of these vlans down.
>
> That deals only with keeping interfaces present to dnsmasq.
> Nothing about a moving client.
>
>
> Thing is that poor problem descriptions do not contribute
> to improvement.
>
>
> Not your mom
>
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