[Dnsmasq-discuss] Reverse of option 121

[Geert Stappers]

On Thu, Jan 31, 2019 at 06:59:25PM +0100, Daniel Huhardeaux wrote:
> Le 31/01/2019 à 17:51, Geert Stappers a écrit :
> > On Tue, Jan 29, 2019 at 01:51:39PM +0100, Daniel Huhardeaux wrote:
> > > Le 28/01/2019 à 20:11, Geert Stappers a écrit :
> > > > On Mon, Jan 28, 2019 at 06:44:22PM +0100, Daniel Huhardeaux wrote:
> > > > > Hi,
> > > > > 
> > > > > I have a setup where 3 VLANs are involved and stateless-static-route
> > > > > are sended for one of them. Some devices can be part of one or
> > > > > another of this VLANs.
> > > > > 
> > > > > Problem is that if a device was connected to the VLAN who sended
> > > > > the static-routes, when switching to one of the other VLAN the
> > > > > static-routes are still there.
> > > > > 
> > > > > Is there a way to remove static routes via a dhcp option ? Opposite
> > > > > of option 121 ?
> > > > > 
> > > > > Thanks for any hint
> > > > > 
> > > > 
> > > > On Linux with NetworkManager are all routes over a device deleted
> > > > whenever the device is disconnected.
> > > > 
> > > > So when you have a disconnect upon VLAN hop-over you are fine.
> > > > 
> > > > Upon connect happens another DHCP including  option 121 static routes.
> > > 
> > > I face this problem with Windows client (8.1)
> > > 
> > 
> > But a disconnect is seen by that client while switching VLAN?
> 
> No, that's my problem. At this time I'm looking to find a way to tell
> Windows to delete all routes when changing SSID.
> 
> It seems that even a reboot doesn't delete those static routes.
> 

FWIW   I just came across this


| option rfc3442-classless-static-routes code 121 = array of integer 8;
| option ms-classless-static-routes code 249 = array of integer 8;
| 
| option rfc3442-classless-static-routes 24, 172,24,4, 172,24,0,4,  24, 192,168,72, 172,24,0,4,  0, 172,24,0,1;
| option ms-classless-static-routes      24, 172,24,4, 172,24,0,4,  24, 192,168,72, 172,24,0,4,  0, 172,24,0,1;

It is ISC dhcp server configuration saying

  ip route add 172.24.4.0/24 via 172.24.0.4
  ip route add 192.168.72.0/24 via 172.24.0.4
  ip route add default via 172.24.0.1

twice.  Once in standard and once for Microsoft systems.

Thing I'm trying to say:

 When those wierd Microsoft systems consider option 121 as persistent,
 maybe you can try option 249.


Groeten
Geert Stappers
-- 
Leven en laten leven