VLANS and DHCP

Fri Aug 18 14:37:20 UTC 2006

I know everyone has given ideas on what you *should* do, but here is how to
do exactly what you originally asked:

create files for each vlan in
/etc/sysconfig/networking-scripts/ifcfg-eth0.<vlan tag id>

which contains the following:

DEVICE=eth1.<vlan tag id>
IPADDR=10.39.108.47
NETMASK=255.255.255.0
ONBOOT=yes
VLAN=yes

The important part is the VLAN=yes line.  Run service network stop/start or
whatever equivalent on your FC5 machine.  You can see the interfaces with
ifconfig and can control them just like any other interface.

I had to do this for one portion of our setup behind a firewall since the
pix didn't pass dhcp requests like a normal router.

Good luck.

Allie

                      "Steve Wenger"                                                                                                  
                      <steve at nconnectwi        To:       dhcp-users at isc.org                                                           
                      reless.com>              cc:       (bcc: Allie M Hopkins/allie/LSU)                                             
                      Sent by:                 Subject:  Re: VLANS and DHCP                                                           
                      dhcp-users-bounce                                                                                               
                      @isc.org                                                                                                        

                      08/17/2006 11:17                                                                                                
                      PM                                                                                                              
                      Please respond to                                                                                               
                      dhcp-users                                                                                                      

I will be running it on Fedora Core 5,  I am going to have approx 100 total

vlans to start, and I know it can be done I am just not sure how to get it
done.

Steve Wenger
Nconnect Internet and High Speed Wireless.
Got a need for speed?  We have a solution for you!

-----Original Message-----
From: Michael Loftis <mloftis at wgops.com>
To: dhcp-users at isc.org
Date: Thu, 17 Aug 2006 20:27:59 -0600
Subject: Re: VLANS and DHCP

>
> --On August 17, 2006 9:09:53 PM -0500 Steve Wenger
> <steve at nconnectwireless.com> wrote:
>
> > I am currently running a wireless network with over 2ooo clients
> attached
> > to  50 different access points,  I will be reconfiguring the network
> and
> > setting  up different VLANS for each tower location.  I want to use
> one
> > centralized  DHCP server so I need to configure a DHCP server that
> can
> > assign clients  addresses from multiple address blocks both public
> and
> > private based upon  the VLAN that the client is part of.  Can anyone
> > point me to some  documentation on how to accomplish this.
> > Steve Wenger
> > Nconnect Internet and High Speed Wireless.
> > Got a need for speed?  We have a solution for you!
>
> What platform?  Linux and FreeBSD both support an 802.1q/VLAN
> encapsulation
> driver.  I've used both to run DHCP and they work very well.  They both
> expose an interface to DHCPd, so there's nothing 'special' as far as
> DHCPd
> is concerned.  In Linux there's an option you have to sometimes set
> that
> makes sure the Layer2 Ethernet headers are correct in order to make
> certain
> the DHCPd works.  In any case it's not the DHCPd that does the VLAN
> interface, it's the host OS.
>