[Dnsmasq-discuss] DHCP problem when moving from one WiFi SSID to another

[john doe]

On 12/26/2018 6:58 PM, Chris Green wrote:
> I have a large[ish[ house and to provide good WiFi throughout I run
> two Draytek routers.  The 'main' one is a Vigor 2860n which connects
> to the internet by FTTC, the second one is an old Vigor 2820n which
> has its WAN disabled and the LAN hardwired to the 2860n LAN.
> 
> Currently I'm using the same SSID on both routers, I've read quite a
> lot around this and the weight of opinion seems to be that using the
> same SSID should work OK and is more transparent to the user than
> using different ones.  However I have also tried different SSIDs for
> the two routers requiring user intervention to move from one to the
> other, this shows the same symptoms (described below) as using the
> same SSID.
> 
> What happens is that when I move around such that the WiFi connection
> should move from the 2820n to the 2860n my laptop loses its IP
> address.
> 
> DHCP and DNS is provided by dnsmasq running on a RaspberryPi, the
> basic IPV4 setup is as follows:-
> 
>     Vigor 2860n - 192.168.1.1
>     Raspberry Pi - 192.168.1.2 (runs dnsmasq)
>     Desktop 192.168.1.3
>     Vigor 2820n - 192.168.1.20
> 
> The Pi assigns IP addresses from 192.168.80 to 192.168.1.127 and the
> conf file is:-
> 
>     domain-needed
>     bogus-priv
>     expand-hosts
>     domain=zbmc.eu
>     dhcp-range=192.168.1.80,192.168.1.127,12h
>     dhcp-option=3,192.168.1.1
>     local=/zbmc.eu/
>     cname=bbb,beaglebone
>     cname=mx201,maxine-X201
>     cname=ben,DESKTOP-978VD5M
>     cname=oki,MC342-AE529C
>     dhcp-host=00:BB:3A:E9:A3:15,maxineKindle
>     dhcp-host=00:09:B0:C9:CE:81,onkyoTx-nr616
>     dhcp-host=28:EF:01:2D:EB:07,chrisKindle
>     dhcp-host=08:EB:74:9D:47:53,humaxFreeview
>     dhcp-host=2C:08:8C:CC:9A:9E,humaxYouview
>     dhcp-host=00:1F:E2:4E:8F:CA,maxineStudy
>     dhcp-host=00:25:36:AE:52:9C,192.168.1.50
> 
> 
> My laptop seems to lose its IP address whenever I move from one
> Draytek's WiFi to the other but only when the IP is assigned by
> dnsmasq.  If I connect to my guest network (192.168.6.x) then I get a
> IP address assigned by the 2860n and a good connection to the outside
> world.  If I then reconnect to the 'local' WiFi the laptop loses its
> IP address.  It's as if dnsmasq doesn't see the disconnection and
> doesn't answer the new DHCP broadcast from my laptop.  If I leave it
> disconnected for a minute or two and then re-connect to the WiFi it
> *does* get an IP.
> 
> 
> Can anyone explain what might be wrong and/or a fix or workaround?
> 
> 

How is this issue different from the one you posted a fiew mounths back (1)?

Did you try what Simon Kellie suggested then?

1)
http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2018q2/012225.html

-- 
John Doe