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DHCP on a dialer interface for PPPOE passthough

David Belyea
Level 1
Level 1

Hi peoples

I have a questions about getting dhcp working on a dialer interface I have 881 routers around (and other versions) all of the use this kinda of config

in this case its a vdsl modem on f4 , other places it a dsl router in PPPOE bridge mode all do the same thing

interface Dialer1
 mtu 1492
 bandwidth 12000
 bandwidth receive 11000
 ip dhcp client lease 1 0 0
 ip address negotiated
 ip nbar protocol-discovery
 ip nat outside
 ip virtual-reassembly in
 encapsulation ppp
 ip tcp adjust-mss 1360
 load-interval 60
 dialer pool 1
 ppp authentication chap pap callin
 ppp chap hostname *****
 ppp chap password 7 122222222222
 ppp pap sent-username ******* password 7 23333333333
 service-policy output Dialer1

this issue I have is when I try and set the ip address neg (working) to ip address dhcp (not working) I get the debug below

before the debug I have tryied

no ip dhcp client request tftp-server-address

1 day lease

enable shcp relay on the interface fast 4

so I'm totally out of ideas

TW-RTR-01(config-if)#no sh
DHCP: DHCP client process started: 10
DHCP: Waiting for 5 seconds on interface Dialer1 to come up
Sep  3 23:31:29.936: %LINK-3-UPDOWN: Interface Dialer1, changed state to up
Sep  3 23:31:31.148: RAC: Starting DHCP discover on Dialer1
Sep  3 23:31:31.148: DHCP: Try 1 to acquire address for Dialer1
Sep  3 23:31:31.148: DHCP: allocate request
Sep  3 23:31:31.148: DHCP: new entry. add to queue, interface Dialer1
Sep  3 23:31:31.148: DHCP: Client socket is opened
Sep  3 23:31:31.148: DHCP: SDiscover attempt # 1 for entry:
Sep  3 23:31:31.148: Temp IP addr: 0.0.0.0  for peer on Interface: Dialer1
Sep  3 23:31:31.148: Temp  sub net mask: 0.0.0.0
Sep  3 23:31:31.148:    DHCP Lease server: 0.0.0.0, state: 3 Selecting
Sep  3 23:31:31.148:    DHCP transaction id: 755
Sep  3 23:31:31.148:    Lease: 0 secs,  Renewal: 0 secs,  Rebind: 0 secs
Sep  3 23:31:31.148:    Next timer fires after: 00:00:04
Sep  3 23:31:31.148:    Retry count: 1   Client-ID: cisco-885a.9262.f3a4-Di1
Sep  3 23:31:31.152:    Client-ID hex dump: 636973636F2D383835612E393236322E
Sep  3 23:31:31.152:                        663361342D446931
Sep  3 23:31:31.152:    Hostname: TW-RTR-01
Sep  3 23:31:31.152: DHCP: SDiscover placed class-id option: 636973636F706E70
Sep  3 23:31:31.152: DHCP: SDiscover: sending 306 byte length DHCP packet
Sep  3 23:31:31.152: DHCP: SDiscover 306 bytes
Sep  3 23:31:31.152:             B'cast on Dialer1 interface from 0.0.0.0
Sep  3 23:31:34.804: DHCP: SDiscover attempt # 2 for entry:
Sep  3 23:31:34.804: Temp IP addr: 0.0.0.0  for peer on Interface: Dialer1
Sep  3 23:31:34.804: Temp  sub net mask: 0.0.0.0
Sep  3 23:31:34.804:    DHCP Lease server: 0.0.0.0, state: 3 Selecting
Sep  3 23:31:34.804:    DHCP transaction id: 755
Sep  3 23:31:34.804:    Lease: 0 secs,  Renewal: 0 secs,  Rebind: 0 secs
Sep  3 23:31:34.804:    Next timer fires after: 00:00:04
Sep  3 23:31:34.804:    Retry count: 2   Client-ID: cisco-885a.9262.f3a4-Di1
Sep  3 23:31:34.804:    Client-ID hex dump: 636973636F2D383835612E393236322E
Sep  3 23:31:34.804:                        663361342D446931
Sep  3 23:31:34.804:    Hostname: TW-RTR-01
Sep  3 23:31:34.804: DHCP: SDiscover placed class-id option: 636973636F706E70
Sep  3 23:31:34.804: DHCP: SDiscover: sending 306 byte length DHCP packet
Sep  3 23:31:34.804: DHCP: SDiscover 306 bytes
Sep  3 23:31:34.804:             B'cast on Dialer1 interface from 0.0.0.0
Sep  3 23:31:38.804: DHCP: SDiscover attempt # 3 for entry:
Sep  3 23:31:38.804: Temp IP addr: 0.0.0.0  for peer on Interface: Dialer1
Sep  3 23:31:38.804: Temp  sub net mask: 0.0.0.0
Sep  3 23:31:38.804:    DHCP Lease server: 0.0.0.0, state: 3 Selecting
Sep  3 23:31:38.804:    DHCP transaction id: 755
Sep  3 23:31:38.804:    Lease: 0 secs,  Renewal: 0 secs,  Rebind: 0 secs
Sep  3 23:31:38.804:    Next timer fires after: 00:00:04
Sep  3 23:31:38.804:    Retry count: 3   Client-ID: cisco-885a.9262.f3a4-Di1
Sep  3 23:31:38.804:    Client-ID hex dump: 636973636F2D383835612E393236322E
Sep  3 23:31:38.804:                        663361342D446931
Sep  3 23:31:38.804:    Hostname: TW-RTR-01
Sep  3 23:31:38.804: DHCP: SDiscover placed class-id option: 636973636F706E70
Sep  3 23:31:38.804: DHCP: SDiscover: sending 306 byte length DHCP packet
Sep  3 23:31:38.804: DHCP: SDiscover 306 bytes
Sep  3 23:31:38.804:             B'cast on Dialer1 interface from 0.0.0.0
Sep  3 23:31:42.804: DHCP: QScan: Timed out Selecting state
TW-RTR-01(config-if)#
TW-RTR-01(config-if)#sh
Sep  3 23:31:48.964: %DIALER-6-BIND: Interface Vi2 bound to profile Di1
Sep  3 23:31:48.964: %CRYPTO-6-ISAKMP_ON_OFF: ISAKMP is OFF
Sep  3 23:31:48.968: %LINK-3-UPDOWN: Interface Virtual-Access2, changed state to up
Sep  3 23:31:49.416: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access2, changed state to up%Unknown DHCP problem.. No allocation possible
Sep  3 23:31:51.648: DHCP: Waiting for 5 seconds on interface Dialer1
Sep  3 23:31:56.648: DHCP: Try 2 to acquire address for Dialer1
Sep  3 23:31:56.648: DHCP: allocate request
Sep  3 23:31:56.648: DHCP: zapping entry in DHC_PURGING state for Di1
Sep  3 23:31:56.648: DHCP: deleting entry 8EBF38BC 0.0.0.0 from list
Sep  3 23:31:56.648: Temp IP addr: 0.0.0.0  for peer on Interface: Dialer1
Sep  3 23:31:56.648: Temp  sub net mask: 0.0.0.0
Sep  3 23:31:56.648:    DHCP Lease server: 0.0.0.0, state: 11 Purging
Sep  3 23:31:56.648:    DHCP transaction id: 755
Sep  3 23:31:56.648:    Lease: 0 secs,  Renewal: 0 secs,  Rebind: 0 secs
Sep  3 23:31:56.648:    Next timer fires after: 00:00:26
Sep  3 23:31:56.648:    Retry count: 0   Client-ID: cisco-885a.9262.f3a4-Di1
Sep  3 23:31:56.648:    Client-ID hex dump: 636973636F2D383835612E393236322E
Sep  3 23:31:56.652:                        663361342D446931
Sep  3 23:31:56.652:    Hostname: TW-RTR-01
Sep  3 23:31:56.652: DHCP: new entry. add to queue, interface Dialer1
Sep  3 23:31:56.652: DHCP: SDiscover attempt # 1 for entry:
Sep  3 23:31:56.652: Temp IP addr: 0.0.0.0  for peer on Interface: Dialer1
Sep  3 23:31:56.652: Temp  sub net mask: 0.0.0.0
Sep  3 23:31:56.652:    DHCP Lease server: 0.0.0.0, state: 3 Selecting
Sep  3 23:31:56.652:    DHCP transaction id: 756
Sep  3 23:31:56.652:    Lease: 0 secs,  Renewal: 0 secs,  Rebind: 0 secs
Sep  3 23:31:56.652:    Next timer fires after: 00:00:04
Sep  3 23:31:56.652:    Retry count: 1   Client-ID: cisco-885a.9262.f3a4-Di1
Sep  3 23:31:56.652:    Client-ID hex dump: 636973636F2D383835612E393236322E
Sep  3 23:31:56.652:                        663361342D446931
Sep  3 23:31:56.652:    Hostname: TW-RTR-01
Sep  3 23:31:56.652: DHCP: SDiscover placed class-id option: 636973636F706E70
Sep  3 23:31:56.652: DHCP: SDiscover: sending 306 byte length DHCP packet
Sep  3 23:31:56.652: DHCP: SDiscover 306 bytes
Sep  3 23:31:56.652:             B'cast on Dialer1 interface from 0.0.0.0
TW-RTR-01(config-if)#
Sep  3 23:31:58.652: DHCP: Release IPL called for interface Dialer1 in state 3
Sep  3 23:31:58.652: RAC: DHCP stopped on interface Dialer1
Sep  3 23:31:58.656: %DIALER-6-UNBIND: Interface Vi2 unbound from profile Di1
Sep  3 23:31:58.660: Di1 DDR: dialer shutdown complete
Sep  3 23:31:58.664: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access2, changed state to down
TW-RTR-01(config-if)#
Sep  3 23:31:58.664: %LINK-3-UPDOWN: Interface Virtual-Access2, changed state to down
TW-RTR-01(config-if)#sh
TW-RTR-01(config-if)#
Sep  3 23:32:00.660: %LINK-5-CHANGED: Interface Dialer1, changed state to administratively downip add
2 Replies 2

Hello,

you use either DHCP or PPP, both won't work together. Since your dialer interface is configured for ppp encapsulation, it uses IPCP, which is a different negotiation process than DHCP. Are the routers connected to ISP's ?

devils_advocate
Level 7
Level 7

Are you sure you need the DHCP client command below?

 interface Dialer1 

 mtu 1492
 bandwidth 12000
 bandwidth receive 11000
 ip dhcp client lease 1 0 0
 ip address negotiated
 ip nbar protocol-discovery
 ip nat outside
 ip virtual-reassembly in
 encapsulation ppp
 ip tcp adjust-mss 1360
 load-interval 60
 dialer pool 1
 ppp authentication chap pap callin
 ppp chap hostname *****
 ppp chap password 7 122222222222
 ppp pap sent-username ******* password 7 23333333333
 service-policy output Dialer1

PPPoE will get an IP address from the DSL provider as it has the 'ip address negotiated' command.

Try and remove the DHCP client command and see if you get an address.

Thanks