Cisco 881 cant to obtain ip from ISP dhcp-server

[kallugin2011]

Hi. I cant to obtain DHCP-address on WAN interface. All over hardware can (windows-based systems and Asus RT-N10), but not Cisco 881

Also i cant to obtain ip even from Asus RT-N10 with this configuration:

!
version 15.1
service config
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
memory-size iomem 10
ip source-route
!
!
!
!
!
ip cef
no ipv6 cef
!
!
crypto pki token default removal timeout 0
!
!
license udi pid CISCO881-K9 sn FCZ1523C3RR
!
!
username admin privilege 15 secret 5 $1$0H8v$xx/HtPJIllcFvEWFjzI5t/
!
!
!
!
!
!
interface FastEthernet0
!
interface FastEthernet1
!
interface FastEthernet2
!
interface FastEthernet3
!
interface FastEthernet4
ip address dhcp
ip broadcast-address 0.0.0.0
duplex auto
speed auto
!
interface Vlan1
ip address 192.168.4.1 255.255.255.0
ip broadcast-address 0.0.0.0
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
logging esm config
!
!
!
!
!
control-plane
!
!
line con 0
exec-timeout 0 0
logging synchronous
login local
no modem enable
line aux 0
line vty 0 4
exec-timeout 0 0
logging synchronous
login local
transport input all
!
end

After thousands experiments next configuration started to obtain ip from Asus RT-N10 , but not from ISP

!
! Last configuration change at 12:22:25 UTC Tue Sep 13 2011 by admin
!
version 15.1
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot system flash c880data-universalk9-mz.151-3.T.bin
boot-end-marker
!
!
!
no aaa new-model
memory-size iomem 10
ip source-route
!
!
!
ip dhcp relay information trust-all
ip dhcp compatibility suboption link-selection standard
!
!
ip cef
no ip dhcp-client broadcast-flag
no ipv6 cef
!
!
crypto pki token default removal timeout 0
!
!
license udi pid CISCO881-K9 sn FCZ1523C3RR
!
!
username admin privilege 15 secret 5 $1$3bFL$y/cxqQLd.8cixPrtETEJ4.
!
!
!
!
!
!
interface FastEthernet0
!
interface FastEthernet1
!
interface FastEthernet2
!
interface FastEthernet3
!
interface FastEthernet4
ip dhcp relay information trusted
ip dhcp relay information check-reply none
no ip dhcp client request tftp-server-address
no ip dhcp client request netbios-nameserver
no ip dhcp client request vendor-specific
no ip dhcp client request static-route
ip address dhcp
ip broadcast-address 0.0.0.0
duplex auto
speed auto
!
interface Vlan1
no ip address
ip broadcast-address 0.0.0.0
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
logging esm config
!
!
!
!
!
control-plane
!
!
line con 0
exec-timeout 0 0
logging synchronous
login local
no modem enable
line aux 0
line vty 0 4
exec-timeout 0 0
logging synchronous
login local
transport input all
!
end

ISP's hardware based on Juniper.

What else must I switch of/on to start DHCP-client?!

[cadet alain]

Hi,

are you doing PPoE with your ISP ? if so then you must obtain IP address from IPCP part of PPP with the ip address negotiated command  under the ethernet interface and you must configure a dialer interface and  bring up the 2.

There are lots of configs here on this forum if this is your case.

Regards.

Alain.

[kallugin2011]

No, its not PPOE process, just direct Ethernet connection. But dhcp.

interface FastEthernet4

ip address dhcp

duplex auto

speed auto

- its all what I need to work. But its not work on 881

http://www.cisco.com/en/US/docs/ios/12_3t/12_3t8/feature/guide/gtdhcpcf.html didnt help me

[cadet alain]

Hi,

ok so do a debug on the 881. you can debug ip packet 199 detail where 199 is the following ACL:

access-list 199 permit udp any any bootps

access-list 199 permit udp any bootpc any

you can also debug DHCP with debug dhcp detail

But before doing this be sure you released any ISP served address from other router which you've got from less than 24 hours. then try again and if it still fails then do the debugs I told you about above.

Regards.

Alain.

[kallugin2011]

We purchased another one Cisco 881 today, and new one working properly with same IOS and same configuration. Im shoked. No any versions. Even i used same MAC-address.

[steini]

Hi together,

I had similar strange behavior.

Somtimes i got unexpected config additions like

ip broadcast-address 0.0.0.0

So i removed that entry, but it cames back.
if i executed follwing command, i was able to get an IP once.

conf t

int fa4

ip address dhcp client-id FastEthernet 4

ip broadcast-address 255.255.255.255

This is happend when in the romon Mode (Console->Break@boot->confreg->enabled are:use all zero broadcast) is enabled.

since i disabled it, no ip broadcast-address 0.0.0.0 additions where made :-)

and the DHCP Broadcast are 255.255.255.255.

SecondCase:

Some ISP's dont like The ClientsID that are generated with the "ip address dhcp" - take a look with wireshark.

With the option "ip address dhcp client-id FastEthernet 4" the Client ID is set to the Mac Address of this interface.

Best Regards

steini