ubuntu 用ppp上不了网了！

[wkt]

帮忙看是什么问题？
下面是syslog的有关信息：
Jun 3 19:37:13 ubuntu kernel: [ 264.969731] eth0: link up, 100Mbps, full-duplex, lpa 0x41E1
Jun 3 19:37:22 ubuntu kernel: [ 273.956405] NETDEV WATCHDOG: eth0: transmit timed out
Jun 3 19:37:25 ubuntu kernel: [ 276.952047] eth0: Transmit timeout, status 0d 0000 c07f media 10.
Jun 3 19:37:25 ubuntu kernel: [ 276.952056] eth0: Tx queue start entry 4 dirty entry 0.
Jun 3 19:37:25 ubuntu kernel: [ 276.952060] eth0: Tx descriptor 0 is 0008203c. (queue head)
Jun 3 19:37:25 ubuntu kernel: [ 276.952064] eth0: Tx descriptor 1 is 0008203c.
Jun 3 19:37:25 ubuntu kernel: [ 276.952066] eth0: Tx descriptor 2 is 0008203c.
Jun 3 19:37:25 ubuntu kernel: [ 276.952069] eth0: Tx descriptor 3 is 0008203c.
Jun 3 19:37:25 ubuntu kernel: [ 276.952087] eth0: link up, 100Mbps, full-duplex, lpa 0x41E1
Jun 3 19:37:30 ubuntu pppd[6091]: Timeout waiting for PADO packets
Jun 3 19:37:30 ubuntu pppd[6091]: Unable to complete PPPoE Discovery
Jun 3 19:37:30 ubuntu pppd[6091]: Terminating on signal 15
Jun 3 19:37:30 ubuntu pppd[6091]: Exit.
Jun 3 19:37:34 ubuntu kernel: [ 285.938892] NETDEV WATCHDOG: eth0: transmit timed out
Jun 3 19:37:37 ubuntu kernel: [ 288.934537] eth0: Transmit timeout, status 0d 0000 c07f media 10.
Jun 3 19:37:37 ubuntu kernel: [ 288.934546] eth0: Tx queue start entry 4 dirty entry 0.
Jun 3 19:37:37 ubuntu kernel: [ 288.934550] eth0: Tx descriptor 0 is 0008203c. (queue head)
Jun 3 19:37:37 ubuntu kernel: [ 288.934554] eth0: Tx descriptor 1 is 0008203c.
Jun 3 19:37:37 ubuntu kernel: [ 288.934556] eth0: Tx descriptor 2 is 0008203c.
Jun 3 19:37:37 ubuntu kernel: [ 288.934559] eth0: Tx descriptor 3 is 00082052.
Jun 3 19:37:37 ubuntu kernel: [ 288.934577] eth0: link up, 100Mbps, full-duplex, lpa 0x41E1
Jun 3 19:37:38 ubuntu kernel: [ 289.960597] NET: Registered protocol family 24
Jun 3 19:37:46 ubuntu kernel: [ 297.921381] NETDEV WATCHDOG: eth0: transmit timed out
Jun 3 19:37:49 ubuntu kernel: [ 300.917045] eth0: Transmit timeout, status 0d 0000 c07f media 10.
Jun 3 19:37:49 ubuntu kernel: [ 300.917055] eth0: Tx queue start entry 4 dirty entry 0.
Jun 3 19:37:49 ubuntu kernel: [ 300.917058] eth0: Tx descriptor 0 is 0008203c. (queue head)
Jun 3 19:37:49 ubuntu kernel: [ 300.917062] eth0: Tx descriptor 1 is 0008203c.
Jun 3 19:37:49 ubuntu kernel: [ 300.917064] eth0: Tx descriptor 2 is 0008203c.
Jun 3 19:37:49 ubuntu kernel: [ 300.917067] eth0: Tx descriptor 3 is 00082052.
Jun 3 19:37:49 ubuntu kernel: [ 300.917086] eth0: link up, 100Mbps, full-duplex, lpa 0x41E1
Jun 3 19:37:57 ubuntu pppoe-discovery: Timeout waiting for PADO packets
Jun 3 19:37:58 ubuntu kernel: [ 309.903871] NETDEV WATCHDOG: eth0: transmit timed out
Jun 3 19:38:01 ubuntu kernel: [ 312.899515] eth0: Transmit timeout, status 0d 0000 c07f media 10.
Jun 3 19:38:01 ubuntu kernel: [ 312.899523] eth0: Tx queue start entry 4 dirty entry 0.
Jun 3 19:38:01 ubuntu kernel: [ 312.899528] eth0: Tx descriptor 0 is 0008203c. (queue head)
Jun 3 19:38:01 ubuntu kernel: [ 312.899531] eth0: Tx descriptor 1 is 0008203c.
Jun 3 19:38:01 ubuntu kernel: [ 312.899534] eth0: Tx descriptor 2 is 0008203c.
Jun 3 19:38:01 ubuntu kernel: [ 312.899536] eth0: Tx descriptor 3 is 0008203c.
Jun 3 19:38:01 ubuntu kernel: [ 312.899554] eth0: link up, 100Mbps, full-duplex, lpa 0x41E1