И что делать? Как это исправить? В Windows же все нормально, дело не в провайдере.

А также назовите вашего провайдера.

Какова версия прошивки модема? (Device Info).

Device Info
Board ID: 96332CG
Software Version: RU_DSL-2500U_1.00_11162007
Bootloader (CFE) Version: (before 1.0.37-5.12)

System Log

Date/Time Facility Severity Message
Jan 1 00:00:16 syslog emerg BCM96345 started: BusyBox v1.00 (2007.11.16-12:29+0000)
Jan 1 00:00:16 user notice kernel: klogd started: BusyBox v1.00 (2007.11.16-12:29+0000)
Jan 1 00:00:16 user warn kernel: Linux version 2.6.8.1 (jenny@BS5) (gcc version 3.4.2) #1 Fri Nov 16 20:28:20 CST 2007
Jan 1 00:00:16 user warn kernel: Serial flash device: name S25FL016A, id 0x0114, size 2048KB
Jan 1 00:00:16 user warn kernel: 96332CG prom init
Jan 1 00:00:16 user warn kernel: CPU revision is: 00029010
Jan 1 00:00:16 user warn kernel: Determined physical RAM map:
Jan 1 00:00:16 user warn kernel: memory: 007a0000 @ 00000000 (usable)
Jan 1 00:00:16 user debug kernel: On node 0 totalpages: 1952
Jan 1 00:00:16 user debug kernel: DMA zone: 1952 pages, LIFO batch:1
Jan 1 00:00:16 user debug kernel: Normal zone: 0 pages, LIFO batch:1
Jan 1 00:00:16 user debug kernel: HighMem zone: 0 pages, LIFO batch:1
Jan 1 00:00:16 user warn kernel: Built 1 zonelists
Jan 1 00:00:16 user warn kernel: Kernel command line: root=31:0 ro noinitrd console=ttyS0,115200
Jan 1 00:00:16 user warn kernel: brcm mips: enabling icache and dcache...
Jan 1 00:00:16 user warn kernel: Primary instruction cache 16kB, physically tagged, 2-way, linesize 16 bytes.
Jan 1 00:00:16 user warn kernel: Primary data cache 8kB 2-way, linesize 16 bytes.
Jan 1 00:00:16 user warn kernel: PID hash table entries: 32 (order 5: 256 bytes)
Jan 1 00:00:16 user warn kernel: Using 120.000 MHz high precision timer.
Jan 1 00:00:16 user warn kernel: Dentry cache hash table entries: 2048 (order: 1, 8192 bytes)
Jan 1 00:00:16 user warn kernel: Inode-cache hash table entries: 1024 (order: 0, 4096 bytes)
Jan 1 00:00:16 user info kernel: Memory: 5692k/7808k available (1510k kernel code, 2096k reserved, 221k data, 76k init, 0k highmem)
Jan 1 00:00:16 user warn kernel: Calibrating delay loop... 239.20 BogoMIPS
Jan 1 00:00:16 user warn kernel: Mount-cache hash table entries: 512 (order: 0, 4096 bytes)
Jan 1 00:00:16 user warn kernel: Checking for 'wait' instruction... unavailable.
Jan 1 00:00:16 user info kernel: NET: Registered protocol family 16
Jan 1 00:00:16 user warn kernel: Total Flash size: 2048K with 32 sectors
Jan 1 00:00:16 user warn kernel: File system address: 0xbfc10100
Jan 1 00:00:16 user warn kernel: Can't analyze prologue code at 80188224
Jan 1 00:00:16 user info kernel: Initializing Cryptographic API
Jan 1 00:00:16 user info kernel: PPP generic driver version 2.4.2
Jan 1 00:00:16 user info kernel: PPP Deflate Compression module registered
Jan 1 00:00:16 user info kernel: PPP BSD Compression module registered
Jan 1 00:00:16 user info kernel: MPPE/MPPC encryption/compression module registered
Jan 1 00:00:16 user info kernel: NET: Registered protocol family 24
Jan 1 00:00:16 user warn kernel: Using noop io scheduler
Jan 1 00:00:16 user warn kernel: bcm963xx_mtd driver v1.0
Jan 1 00:00:16 user warn kernel: brcmboard: brcm_board_init entry
Jan 1 00:00:16 user warn kernel:
Jan 1 00:00:16 user warn kernel: ======= GPIO CONFIG_BCM96338 inited ========
Jan 1 00:00:16 user info kernel: Serial: BCM63XX driver $Revision: 3.00 $
Jan 1 00:00:16 user warn kernel: ttyS0 at MMIO 0xfffe0300 (irq = 10) is a BCM63XX
Jan 1 00:00:16 user info kernel: NET: Registered protocol family 2
Jan 1 00:00:16 user info kernel: IP: routing cache hash table of 512 buckets, 4Kbytes
Jan 1 00:00:16 user info kernel: TCP: Hash tables configured (established 512 bind 1024)
Jan 1 00:00:16 user warn kernel: ip_conntrack version 2.1 (61 buckets, 0 max) - 376 bytes per conntrack
Jan 1 00:00:16 user warn kernel: ip_tables: (C) 2000-2002 Netfilter core team
Jan 1 00:00:16 user info kernel: Initializing IPsec netlink socket
Jan 1 00:00:16 user debug syslog: echo > /var/snmpd.conf
Jan 1 00:00:16 user info kernel: NET: Registered protocol family 1
Jan 1 00:00:17 user info kernel: NET: Registered protocol family 17
Jan 1 00:00:17 user info kernel: NET: Registered protocol family 15
Jan 1 00:00:17 user notice kernel: Ebtables v2.0 registered
Jan 1 00:00:17 user info kernel: NET: Registered protocol family 8
Jan 1 00:00:17 user info kernel: NET: Registered protocol family 20
Jan 1 00:00:17 user info kernel: 802.1Q VLAN Support v1.8 Ben Greear
Jan 1 00:00:17 user info kernel: All bugs added by David S. Miller
Jan 1 00:00:17 user warn kernel: VFS: Mounted root (squashfs filesystem) readonly.
Jan 1 00:00:17 user info kernel: Freeing unused kernel memory: 76k freed
Jan 1 00:00:17 user warn kernel: Algorithmics/MIPS FPU Emulator v1.5
Jan 1 00:00:17 user warn kernel: atmapi: module license 'Proprietary' taints kernel.
Jan 1 00:00:17 user warn kernel: adsl: adsl_init entry
Jan 1 00:00:17 user warn kernel: blaadd: blaa_detect entry
Jan 1 00:00:17 user info kernel: Broadcom BCMPROCFS v1.0 initialized
Jan 1 00:00:17 user warn kernel: Broadcom BCM6338A2 Ethernet Network Device v0.3 Nov 16 2007 20:27:28
Jan 1 00:00:17 user warn kernel: Config Internal PHY Through MDIO
Jan 1 00:00:17 user info kernel: BCM63xx_ENET: 100 MB Full-Duplex (auto-neg)
Jan 1 00:00:17 user warn kernel: eth0: MAC Address: 00:1C:F0:17:83:62
Jan 1 00:00:17 user crit kernel: eth0 Link UP.
Jan 1 00:00:17 user warn kernel: BcmAdsl_Initialize=0xC00733F8, g_pFnNotifyCallback=0xC008BC64
Jan 1 00:00:17 user warn kernel: AnnexCParam=0x7FFF7EB8 AnnexAParam=0x00000980 adsl2=0x00000000
Jan 1 00:00:17 user warn kernel: pSdramPHY=0xA07FFFF8, 0x1B7768 0xDEADBEEF
Jan 1 00:00:17 user warn kernel: AdslCoreHwReset: AdslOemDataAddr = 0xA07FD3D4
Jan 1 00:00:17 user warn kernel: AnnexCParam=0x7FFF7EB8 AnnexAParam=0x00000980 adsl2=0x00000000
Jan 1 00:00:17 user warn kernel: dgasp: kerSysRegisterDyingGaspHandler: dsl0 registered
Jan 1 00:00:17 user warn kernel: ATM proc init !!!
Jan 1 00:00:17 user crit kernel: ADSL G.994 training
Jan 1 00:00:17 user warn kernel: ip_conntrack_pptp version 2.1 loaded
Jan 1 00:00:17 user warn kernel: ip_nat_pptp version 2.0 loaded
Jan 1 00:00:17 user info kernel: device eth0 entered promiscuous mode
Jan 1 00:00:17 user info kernel: br0: port 1(eth0) entering learning state
Jan 1 00:00:17 user info kernel: br0: topology change detected, propagating
Jan 1 00:00:17 user info kernel: br0: port 1(eth0) entering forwarding state
Jan 1 00:00:17 user info kernel: device nas_0_0_35 entered promiscuous mode
Jan 1 00:00:17 user info kernel: br0: port 2(nas_0_0_35) entering learning state
Jan 1 00:00:17 user info kernel: br0: topology change detected, propagating
Jan 1 00:00:17 user info kernel: br0: port 2(nas_0_0_35) entering forwarding state
Jan 1 00:00:17 user debug syslog: echo > /var/hosts
Jan 1 00:00:18 user warn kernel:
Jan 1 00:00:18 user warn kernel: ioctl, p_name=diapd
Jan 1 00:00:18 user crit kernel: ADSL G.992 started
Jan 1 00:00:18 user debug syslog: pppd plugin pppoe nas_0_0_35 nodetach user 'nkchadinpv@intranet' password ********** interface_name 0_0_35_1 usepeerdns refuse-eap persist lcp-echo-interval 30 holdoff 3 nomppc nomppe mtu 1492 &
Jan 1 00:00:20 daemon info pppd[241]: Plugin pppoe loaded.
Jan 1 00:00:20 daemon info pppd[241]: RP-PPPoE plugin version 3.3 compiled against pppd 2.4.3
Jan 1 00:00:20 daemon info pppd[241]: Plugin pppoe called.
Jan 1 00:00:21 daemon notice pppd[241]: pppd 2.4.3 started by admin, uid 0
Jan 1 00:00:22 user crit kernel: ADSL G.992 channel analysis
Jan 1 00:00:28 user crit kernel: ADSL G.992 message exchange
Jan 1 00:00:28 user crit kernel: ADSL link up, interleaved, us=996, ds=6142
Jan 1 00:00:28 user warn kernel: ATM Soft SAR: ATM link connected.
Jan 1 00:00:30 user debug syslog: iptables -t nat -A PREROUTING -i br0 -d 192.168.1.1 -p udp --dport 53 -j DNAT --to 128.9.0.107
Jan 1 00:01:07 daemon warn pppd[241]: Timeout waiting for PADO packets
Jan 1 00:01:08 daemon err pppd[241]: Unable to complete PPPoE Discovery
Jan 1 00:01:46 daemon warn pppd[241]: Timeout waiting for PADO packets
Jan 1 00:01:46 daemon err pppd[241]: Unable to complete PPPoE Discovery
Jan 1 00:02:24 daemon warn pppd[241]: Timeout waiting for PADO packets
Jan 1 00:02:24 daemon err pppd[241]: Unable to complete PPPoE Discovery

В режиме моста все работает? Если "да", то вопрос - не использует ли Ваш провайдер привязку по MAC-адресу?

06:49:45 'mylogin@intranet' (2008.03.05 06:49:45,192.168.205.86:0,Virtual,Framed,PPP,Stop,02038D03,RADIUS,,,10.2.125.106,0,47074,2759436342,5723935265, client-mac-address=0050.8d98.8554, connect-progress=LAN

В режме моста все ОК. Мало того, при таких настройках, которые я вам скинул из Windows нормально подключается.
Привязки к MAC-адресу нет, т.к. на USB-шном модеме (соответственно другое сетевое подключение и другой MAC-адрес) все ок.

Какой тип аутентификации используется Вашим провайдером? (роутер поддерживает только PAP и CHAP).