Re: IP DHCP snooping

Adam is correct. I have a blog on this topic that you might find really
helpful here -
http://astorinonetworks.com/2011/06/28/going-deep-with-dhcp-snooping/

On Sat, Dec 10, 2011 at 7:29 PM, Adam Booth <adam.booth_at_gmail.com> wrote:

> Hi Amin,
>
> On your router if you did a "debug ip dhcp server packet" you would be
> seeing
>
> *Mar 1 00:14:26.511: DHCPD: inconsistent relay information.
> *Mar 1 00:14:26.511: DHCPD: relay information option exists, but giaddr is
> zero
>
> IOS DHCP Servers don't like the DHCP Options that the Switch is now
> including as part of the snooping process.
>
> You can take to resolve this problem two ways:
>
> On the switch include "no ip dhcp snooping information option"
> Or the Router being the DHCP Server "ip dhcp relay information trust-all"
>
> You only need one or the other to get things working. One tells the switch
> to stop adding the options, the other tells the router that all the options
> it receives are ok
>
> Cheers,
> Adam
>
> On Sat, Dec 10, 2011 at 7:13 PM, amin <amin_at_axizo.com> wrote:
>
> > Hi experts,
> >
> >
> >
> > I have a strange issue in configuring DHCP snooping
> >
> >
> >
> > Ip dhcp snooping
> >
> > Ip dhcop snooping vlan 1
> >
> >
> >
> > Int f0/1 ! to the PC
> >
> > Int f0/2 ! to the DHCP server
> >
> > Ip dhcp snooping trust
> >
> >
> >
> > But still it is not working, the PC is not getting ip address, here the
> > debug
> >
> >
> >
> > 00:08:29: DHCP_SNOOPING: received new DHCP packet from input interface
> > (FastEthernet0/2)
> >
> > 00:08:29: DHCP_SNOOPING: process new DHCP packet, message type:
> > DHCPDISCOVER
> >
> > 00:08:29: DHCP_SNOOPING_SW: Encoding opt82 in vlan-mod-port format
> >
> > 00:08:29: DHCP_SNOOPING_SW: bridge packet get invalid mat entry:
> > FFFF.FFFF.FFFF, packet is flooded to ingress VLAN: (1)
> >
> > 00:08:29: DHCP_SNOOPING_SW: bridge packet send packet to port:
> > FastEthernet0/1.
> >
> > 00:08:46: DHCP_SNOOPING: received new DHCP packet from input interface
> > (FastEthernet0/2)
> >
> >
> >
> > 00:08:46: DHCP_SNOOPING: process new DHCP packet, message type:
> > DHCPDISCOVER
> >
> > 00:08:46: DHCP_SNOOPING_SW: Encoding opt82 in vlan-mod-port format
> >
> > 00:08:46: DHCP_SNOOPING_SW: bridge packet get invalid mat entry:
> > FFFF.FFFF.FFFF, packet is flooded to ingress VLAN: (1)
> >
> > 00:08:46: DHCP_SNOOPING_SW: bridge packet send packet to port:
> > FastEthernet0/1.
> >
> > 00:08:51: DHCP_SNOOPING: received new DHCP packet from input interface
> > (FastEthernet0/1)
> >
> >
> >
> > 00:08:51: DHCP_SNOOPING: process new DHCP packet, message type:
> > DHCPDISCOVER
> >
> > 00:08:51: DHCP_SNOOPING_SW: bridge packet get invalid mat entry:
> > FFFF.FFFF.FFFF, packet is flooded to ingress VLAN: (1)
> >
> > 00:08:51: DHCP_SNOOPING_SW: bridge packet output port set is null, packet
> > is
> > dropped.
> >
> > 00:08:55: DHCP_SNOOPING: received new DHCP packet from input interface
> > (FastEthernet0/1)
> >
> > 00:08:55: DHCP_SNOOPING: process new DHCP packet, message type:
> > DHCPDISCOVER
> >
> >
> >
> > Regards,
> >
> > Amin
> >
> >
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-- 
Regards,
Joe Astorino
CCIE #24347
Blog: http://astorinonetworks.com
"He not busy being born is busy dying" - Dylan
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