The cable modem do not get ip from DHcp server | docsis.org

You are here

The cable modem do not get ip from DHcp server

10 posts / 0 new
Last post
ilirnako
The cable modem do not get ip from DHcp server

I am testing a Motorola BSR2000 to connect the modems .In the provisioning server I can not see the dhcp requests from the cmts .
I am not expert in CMTS .Please somebody help me :
The config of my CMTS is:

hostname Motorola-2
!
!
!
service password-encryption
!
username ilir user-group sysadmin
username ilir password 7 c98d2d8acd2876f319b90cdc
username mandi user-group sysadmin
username mandi password 7 710efd4401f69d83c8bc232f48
!
ip ftp password 7 11fdc17e3bfdd3e1
!
ip domain-name abcom.al
ip name-server 80.78.66.66
!
logging buffered 51200
no logging control docsis
logging admin-status unconstrained
logging rate-limit 100 1
logging buffered notifications
logging console errors
!
!
cable cmts type euro
!
!
cable spectrum-group upstream0
band 24000000 65000000
collect interval 1800
hop threshold error 30
hop action frequency 63400000 priority 128
hop action frequency 59700000 priority 128
hop action frequency 56000000 priority 128
hop action frequency 52300000 priority 128
hop action frequency 48600000 priority 128
hop action frequency 44900000 priority 128
hop action frequency 41200000 priority 128
hop action frequency 37500000 priority 128
hop action frequency 33800000 priority 128
hop action frequency 30100000 priority 128
hop action frequency 26400000 priority 128
load-balancing static
!
interface ethernet 0/0
ip address 80.78.67.24 255.255.255.224
no shutdown
!
interface ethernet 0/1
shutdown
!
interface ethernet 0/2
shutdown
!
interface ethernet 0/3
shutdown
!
interface gigaether 0/0
shutdown
!
interface gigaether 0/1
shutdown
!
interface cable 0/0
ip address 192.168.63.1 255.255.255.0
ip address 192.168.65.1 255.255.255.0 secondary
ip helper-address 80.78.67.5
cable helper-address 80.78.67.5 cable-modem
cable helper-address 80.78.67.5 host
cable helper-address 80.78.67.5 mta
no shutdown
no ip mask-reply
no ip unreachables
cable downstream 0 frequency 120000000
no cable downstream 0 shutdown
cable upstream 0 frequency 44900000
cable upstream 0 pre-equalization
cable upstream 0 spectrum-group upstream0
no cable upstream 0 shutdown
no cable upstream 0/0 shutdown
cable upstream 0/1 shutdown
cable upstream 0/2 shutdown
cable upstream 0/3 shutdown
cable upstream 1 shutdown
cable upstream 1/0 shutdown
cable upstream 1/1 shutdown
cable upstream 1/2 shutdown
cable upstream 1/3 shutdown
cable upstream 2 shutdown
cable upstream 2/0 shutdown
cable upstream 2/1 shutdown
cable upstream 2/2 shutdown
cable upstream 2/3 shutdown
cable upstream 3 shutdown
cable upstream 3/0 shutdown
cable upstream 3/1 shutdown
cable upstream 3/2 shutdown
cable upstream 3/3 shutdown
cable dynamic-service authorization-mode disable
cable downstream schedule priority-wfq
no cable wireless downstream modulation qpsk
!
!
!
!
!
!
!
ip route 0.0.0.0 0.0.0.0 80.78.67.1
!
!
!
!
!
packet-cable
dqos shutdown
no em shutdown
no es shutdown
!
!
ipsec
ipsec shutdown
!
!
session-timeout console 0
session-timeout telnet 5
!
telnet session-limit 8
!
!
!
!
!
!
!
no ssh enable
!
!
no logging trap
no logging snmp-trap
logging facility local7
!
!
!
aaa new-model
aaa authentication login default local
aaa authentication enable default local
aaa authorization exec default local
aaa console authentication
aaa console authorization commands default
!
!
!
!
time-of-day server 80.78.67.5
cable shared-secret 7 343ec7ac129056ed026e4bf10ff71b7474
enable rdn-process
!
!
!
!
cable service-class
!
!
!
cable dhcp force-unicast

For provisioning i am using the Incognito software .The server is configured b the support of the incognito .

Regards
Ilir

micabu
IP-Helper

Hi,

you have to configure ip-helper also on Ethernet-Interface.

interface ethernet 0/0
ip address 80.78.67.24 255.255.255.224
ip helper-address 80.78.67.5
no shutdown

hope this helps.
Otherwise try to snif dhcp-request an Interface Ethernet 0/0.

Good luck!

Regards,
Michael

ilirnako
The cable modem do not get ip from DHcp server

Thank you Michael
It is the same again :
Motorola-2#sh cable modem
Interface Prim Connect Timing Rec Ip Address Mac Address
Sid State Offset Power

Cable 0/0/D0/U0/C0 2 dhcp(d) 718 0.2 0.0.0.0 0018.9b68.4b5e

Tomorrow I will sniff the ethernet traffic

Ilir

micabu
dhcp

Hi,

why do you use unicast for dhcp request?

Try to disable cable dhcp force-unicast with:

no cable dhcp force-unicast

Normaly dhcp request are Broadcast!

Good luck!

regards Michael

cmcaldas
You missed something

In the cable interface you need ip dhcp relay info option

I didn't see it there. also, from the dhcp server, can you ping the modem gateway?

Let us know how you make out

Regards
Carl

ilirnako
The cable modem do not get ip from DHcp server

I have put the command: ip dhcp relay information option at the cable interface .
And from the server I can ping the modems gateway .
tomorrow I will install the server in a linux machine to see what happens

Regards

ilir

cmcaldas
Should be all set

Glad it worked, quick question. what dhcp server did you tested with and did the modems go online?
From here if there's a problem it would be with the options on the server or the modem file itself.

Good Luck

~Carl

ilirnako
I am using Incognito server

I am using Incognito server ,that is configured from their support .The parameters at the server I think are OK .The problem is that at the dhcp server logs I can not see the the dhcp requests from CMTS .From the server I can ping the gateway of cable-modems and from cmts I can ping the server (80.78.67.5).If someone want to login at the Motorola cmts : user: cmts pass:cmts

Regards

ilir

cmcaldas
telnet access

telnet: connect to address 80.78.67.5: Connection refused

Think you forgot to add an enable and telnet password. so you don't end up with a ton of people getting into the system, email me the passwords and I'll take a quick look.

cmcaldas@gmail.com

put cmts login for the subject ;-)

bealsm
judging by your TOD line,

judging by your TOD line, your provisioning server has an ip of 80.78.67.5. This is also what your helper IP is.

When you use relay you are having the CMTS take all of the multicast dhcp traffic it hears over the different 'networks' (CM, CPE, MTA) and convert it to unicast with the helper IP as a source address. By having the helper IP the same as the provisioning server, you are causing an arp conflict.

Another trick I picked up that at least applies to Coresma CMTS's (but might to yours as well), is that if you are relaying traffic over to the same subnet as the CMTS, use the CMTS IP as the helper IP. That is, if you are relaying 192.168.63.0/24 network traffic over to the 80.78.67.24/27 network and your CMTS has a management IP on the 80.78.67.24/27 network, then the helper address would be the same as the CMTS. On Coresema's, the helper IP arps the same MAC as the CMTS management IP, so having different CMTS and helper IP's on the same network causes some weird conflict issues.

Log in or register to post comments