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Problems with DHCP Server owned by suscribers

Posted: Fri Aug 03, 2007 6:54 pm
by nesta
Hi

I have several suscribers connected through a Wireless Bridged Network (Motorola Canopy gear), when an user connect a Router SOHO with DHCP enable my customers connect to the nearest DHCP (most of the time the user's router) instead my Central DHCP Server on a Mikrotik Box. Then my customer has to release his leased ip several times, till he gets a correct one.

This is my Network:

MK BOX -- Switch -- AP - - - - Wireless Bridge -- Switch -- User1, User2, User3 .. UserN (SOHO Router)

Is there a way to avoid this ?

I'm using HotSpot on MK Box with HTTP authentication.

Re: Problems with DHCP Server owned by suscribers

Posted: Tue Aug 07, 2007 3:16 pm
by sergejs
Do you have multiple routers with enabled DHCP server within the same broadcast domain ?

Re: Problems with DHCP Server owned by suscribers

Posted: Tue Aug 07, 2007 5:24 pm
by UniKyrn
It's been awhile since I played with Canopy gear, but I think I remember them having the ability to filter packets. You might be able to filter DHCP requests headed towards your customers and DHCP replies coming from them.

Re: Problems with DHCP Server owned by suscribers

Posted: Wed Aug 08, 2007 8:40 pm
by nesta
Do you have multiple routers with enabled DHCP server within the same broadcast domain ?
No, all my suscribers connect directly to my hotspot interface in a Mikrotrik Box, the MK is the Router and also the DHCP Server in hotspot mode. All the suscribers are on the same Network. Even the MK log is reporting "Unknown DHCP Server with the following mac address" when the users connect them.

Re: Problems with DHCP Server owned by suscribers

Posted: Wed Aug 08, 2007 8:45 pm
by nesta
It's been awhile since I played with Canopy gear, but I think I remember them having the ability to filter packets. You might be able to filter DHCP requests headed towards your customers and DHCP replies coming from them.
Yes they have, I've already filtred DHCP Server packets but the issue remains on the directly connected users on the same switch. Then if I have users with DHCP enabled on several Bridged subnetworks I'll also have problems on that sub-networks.

Re: Problems with DHCP Server owned by suscribers

Posted: Wed Aug 08, 2007 8:50 pm
by UniKyrn
You're going to have to put a smarter switch there then, one that can do packet filtering. You could probably build one yourself using RouterO/S, some 4 port ethernet cards and a small PC, or check places like D-Link/NetGear and see if their smart switches have that ability.