Re: IPCP - how to send option

Here is a configuration where R1 imports information from R3 using the
DHCP protocol.
In this scenario, R1 uses its own subnet for DHCP pool/default route,
but imports
DNS/WINS servers and Option 150 from R3.

R1:
interface Serial0/1
 no ip address
 encapsulation ppp
 dialer in-band
 dialer pool-member 1
!
interface Dialer1
 ip address dhcp
 dialer pool 1
!
ip dhcp pool LOCAL
   import all
   network 20.0.0.0 255.255.255.0
   default-router 20.0.0.1
!
interface FastEthernet0/0
 ip address 20.0.0.1 255.255.255.0

R3:
ip dhcp pool POOL
   network 10.0.0.0 255.255.255.0
   dns-server 10.0.0.100 10.0.0.200
   netbios-name-server 10.0.0.100
   option 150 ip 10.0.0.150
   default-router 10.0.0.3
!
interface FastEthernet0/0
 ip address 10.0.0.3 255.255.255.0
!
interface Serial1/2
 ip unnumbered FastEthernet0/0
 encapsulation ppp
 clock rate 128000

R1#show ip dhcp pool

Pool LOCAL :
 Utilization mark (high/low) : 100 / 0
 Subnet size (first/next) : 0 / 0
 Total addresses : 254
 Leased addresses : 0
 Pending event : none
 1 subnet is currently in the pool :
 Current index IP address range Leased addresses
 20.0.0.1 20.0.0.1 - 20.0.0.254 0

R1#show ip dhcp import

Address Pool Name: LOCAL
Domain Name Server(s): 10.0.0.100 10.0.0.200
NetBIOS Name Server(s): 10.0.0.100
TFTP Server Address Option: 10.0.0.150

R3#show ip dhcp binding
Bindings from all pools not associated with VRF:
IP address Client-ID/ Lease expiration Type
                    Hardware address/
                    User name
10.0.0.2 0063.6973.636f.2d30. May 04 2009 10:21 AM Automatic
                    3030.642e.6564.6338.
                    2e34.6636.302d.4469.
                    31

HTH

-- 
Petr Lapukhov, petr_at_INE.com
CCIE #16379 (R&S/Security/SP/Voice)
Internetwork Expert, Inc.
http://www.INE.com
Toll Free: 877-224-8987
Outside US: 775-826-4344
2009/5/3 nowy1981 <freemaxis_at_gmail.com>:
> Thanks Peter,
>
> so second question BTW, how exactly indside interface should be configured
> to assigned IP addresses to the hosts based on the DHCP ODAP feature.
>
> Could you send me any example?
>
> Petr Lapukhov pisze:
>>
>> Hi,
>>
>> If you are referrering to the DHCP option 150, you should run DHCP
>> over PPP, not IPCP. This is accomplished
>> by using the command "ip address dhcp" on the PPP link instead of "ip
>> address negotiated" and is available since IOS 12.2T AFAIR.
>> Naturally, the DHCP pool in the server should be configured with
>> option 150 (TFTP IP) enabled. However, the router will not get much
>> use of the option, unless it import the option into the local DHCP
>> pool (import all + origin dhcp). The only other use of DHCP option 150
>> by the router that comes to mind is AutoInstall over Ethernet.
>>
>> The number of IPCP options is very limited: IP address, DNS/WINS
>> server IP, IP Compression Protocol, Subnet Mask (used by Cisco) and a
>> few more. You may selectively enable some non-default options using
>> the command "ppp ipcp" under the PPP interface configuration mode.
>> You may use those options to seed the local DHCP pool as well (import
>> all + origin ipcp)
>>
>> HTH
>
>
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