Date: Fri, 24 Aug 2001 22:52:19 +0100 (BST) From: Steven Holmes <steg@pc1-east2-0-cust144.ren.cable.ntl.com> To: freebsd-stable@freebsd.org Subject: Re: Weird networking problem Message-ID: <E15aOsF-0000Ce-00@pc1-east2-0-cust144.ren.cable.ntl.com> In-Reply-To: <E15aOe2-0000Bd-00@pc1-east2-0-cust144.ren.cable.ntl.com>
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I updated my source (RELENG_4) about 6 hours ago, and immmediately rebuilt world and then the kernel. > > While trying to access some websites, I discovered a strange > networking problem that I am unable to solve. > > Some IPs I am unable to connect to using TCP. tcpdump shows the SYN > packets that I send to have a bad checksum (I have included a sample > tcpdump output below). However, these are the only packets that > tcpdump shows a problem for, and all my other packets seem to have > correct checksums. > > I can access everything from my internal windows box, which I am > performing NAT for. I am running ipf and ipnat, and have tried > disabling both, but without any result. I have tried with > tcp_extensions both enabled and disabled, have tried a different > network card and have tried with numerous different clients (including > telnet), but the problem remains. > > I get no response to my initial packet (The checksum is always bad), > and this is the only packet that is sent. I am on a cable modem. > > > Sample tcpdump output for accessing www.slashdot.org (a problem IP): > > 22:15:24.687044 pc1-east2-0-cust144.ren.cable.ntl.com.1034 > > 64.28.67.150.http: S [bad tcp cksum fffe!] 1158842795:1158842795(0) > win 16384 <mss 1460> (DF) (ttl 64, id 2222, len 44) > > > kernel configuration: > > # > # GENERIC -- Generic kernel configuration file for FreeBSD/i386 > # > # For more information on this file, please read the handbook section on > # Kernel Configuration Files: > # > # http://www.FreeBSD.org/handbook/kernelconfig-config.html > # > # The handbook is also available locally in /usr/share/doc/handbook > # if you've installed the doc distribution, otherwise always see the > # FreeBSD World Wide Web server (http://www.FreeBSD.org/) for the > # latest information. > # > # An exhaustive list of options and more detailed explanations of the > # device lines is also present in the ./LINT configuration file. If you are > # in doubt as to the purpose or necessity of a line, check first in LINT. > # > # $FreeBSD: src/sys/i386/conf/GENERIC,v 1.246.2.34 2001/08/12 13:13:46 joerg Exp $ > > machine i386 > #cpu I386_CPU > #cpu I486_CPU > cpu I586_CPU > #cpu I686_CPU > ident TRANTOR > maxusers 32 > > #makeoptions DEBUG=-g #Build kernel with gdb(1) debug symbols > > #options MATH_EMULATE #Support for x87 emulation > options INET #InterNETworking > options INET6 #IPv6 communications protocols > options FFS #Berkeley Fast Filesystem > options FFS_ROOT #FFS usable as root device [keep this!] > options SOFTUPDATES #Enable FFS soft updates support > #options MFS #Memory Filesystem > #options MD_ROOT #MD is a potential root device > #options NFS #Network Filesystem > #options NFS_ROOT #NFS usable as root device, NFS required > #options MSDOSFS #MSDOS Filesystem > #options CD9660 #ISO 9660 Filesystem > #options CD9660_ROOT #CD-ROM usable as root, CD9660 required > options PROCFS #Process filesystem > options COMPAT_43 #Compatible with BSD 4.3 [KEEP THIS!] > #options SCSI_DELAY=15000 #Delay (in ms) before probing SCSI > options UCONSOLE #Allow users to grab the console > options USERCONFIG #boot -c editor > #options VISUAL_USERCONFIG #visual boot -c editor > #options KTRACE #ktrace(1) support > options SYSVSHM #SYSV-style shared memory > options SYSVMSG #SYSV-style message queues > options SYSVSEM #SYSV-style semaphores > options P1003_1B #Posix P1003_1B real-time extensions > options _KPOSIX_PRIORITY_SCHEDULING > options ICMP_BANDLIM #Rate limit bad replies > options CPU_SUSP_HLT > options NO_F00F_HACK > options IPFILTER > options IPFILTER_LOG > options KBD_INSTALL_CDEV # install a CDEV entry in /dev > > # To make an SMP kernel, the next two are needed > #options SMP # Symmetric MultiProcessor Kernel > #options APIC_IO # Symmetric (APIC) I/O > > device isa > #device eisa > device pci > > # Floppy drives > device fdc0 at isa? port IO_FD1 irq 6 drq 2 > device fd0 at fdc0 drive 0 > #device fd1 at fdc0 drive 1 > # > # If you have a Toshiba Libretto with its Y-E Data PCMCIA floppy, > # don't use the above line for fdc0 but the following one: > #device fdc0 > > # ATA and ATAPI devices > device ata0 at isa? port IO_WD1 irq 14 > device ata1 at isa? port IO_WD2 irq 15 > device ata > device atadisk # ATA disk drives > device atapicd # ATAPI CDROM drives > device atapifd # ATAPI floppy drives > #device atapist # ATAPI tape drives > options ATA_STATIC_ID #Static device numbering > > # SCSI Controllers > #device ahb # EISA AHA1742 family > #device ahc # AHA2940 and onboard AIC7xxx devices > #device amd # AMD 53C974 (Tekram DC-390(T)) > #device isp # Qlogic family > #device ncr # NCR/Symbios Logic > #device sym # NCR/Symbios Logic (newer chipsets) > #options SYM_SETUP_LP_PROBE_MAP=0x40 > # # Allow ncr to attach legacy NCR devices when > # # both sym and ncr are configured > # > #device adv0 at isa? > #device adw > #device bt0 at isa? > #device aha0 at isa? > #device aic0 at isa? > # > #device ncv # NCR 53C500 > #device nsp # Workbit Ninja SCSI-3 > #device stg # TMC 18C30/18C50 > # > ## SCSI peripherals > #device scbus # SCSI bus (required) > #device da # Direct Access (disks) > #device sa # Sequential Access (tape etc) > #device cd # CD > #device pass # Passthrough device (direct SCSI access) > # > ## RAID controllers interfaced to the SCSI subsystem > #device asr # DPT SmartRAID V, VI and Adaptec SCSI RAID > #device dpt # DPT Smartcache - See LINT for options! > #device mly # Mylex AcceleRAID/eXtremeRAID > # > ## RAID controllers > #device aac # Adaptec FSA RAID, Dell PERC2/PERC3 > #device ida # Compaq Smart RAID > #device amr # AMI MegaRAID > #device mlx # Mylex DAC960 family > #device twe # 3ware Escalade > # > ## atkbdc0 controls both the keyboard and the PS/2 mouse > device atkbdc0 at isa? port IO_KBD > device atkbd0 at atkbdc? irq 1 flags 0x1 > #device psm0 at atkbdc? irq 12 > > device vga0 at isa? > > # splash screen/screen saver > pseudo-device splash > > # syscons is the default console driver, resembling an SCO console > device sc0 at isa? flags 0x100 > > # Enable this and PCVT_FREEBSD for pcvt vt220 compatible console driver > #device vt0 at isa? > #options XSERVER # support for X server on a vt console > #options FAT_CURSOR # start with block cursor > # If you have a ThinkPAD, uncomment this along with the rest of the PCVT lines > #options PCVT_SCANSET=2 # IBM keyboards are non-std > > # Floating point support - do not disable. > device npx0 at nexus? port IO_NPX irq 13 > > # Power management support (see LINT for more options) > device apm0 at nexus? disable flags 0x20 # Advanced Power Management > > # PCCARD (PCMCIA) support > #device card > #device pcic0 at isa? irq 0 port 0x3e0 iomem 0xd0000 > #device pcic1 at isa? irq 0 port 0x3e2 iomem 0xd4000 disable > > # Serial (COM) ports > device sio0 at isa? port IO_COM1 flags 0x10 irq 4 > device sio1 at isa? port IO_COM2 irq 3 > #device sio2 at isa? disable port IO_COM3 irq 5 > #device sio3 at isa? disable port IO_COM4 irq 9 > > # Parallel port > #device ppc0 at isa? irq 7 > #device ppbus # Parallel port bus (required) > #device lpt # Printer > #device plip # TCP/IP over parallel > #device ppi # Parallel port interface device > ##device vpo # Requires scbus and da > > > # PCI Ethernet NICs. > #device de # DEC/Intel DC21x4x (``Tulip'') > #device txp # 3Com 3cR990 (``Typhoon'') > #device vx # 3Com 3c590, 3c595 (``Vortex'') > # > ## PCI Ethernet NICs that use the common MII bus controller code. > ## NOTE: Be sure to keep the 'device miibus' line in order to use these NICs! > device miibus # MII bus support > #device dc # DEC/Intel 21143 and various workalikes > #device fxp # Intel EtherExpress PRO/100B (82557, 82558) > #device pcn # AMD Am79C97x PCI 10/100 NICs > #device rl # RealTek 8129/8139 > #device sf # Adaptec AIC-6915 (``Starfire'') > #device sis # Silicon Integrated Systems SiS 900/SiS 7016 > #device ste # Sundance ST201 (D-Link DFE-550TX) > #device tl # Texas Instruments ThunderLAN > #device tx # SMC EtherPower II (83c170 ``EPIC'') > #device vr # VIA Rhine, Rhine II > #device wb # Winbond W89C840F > #device wx # Intel Gigabit Ethernet Card (``Wiseman'') > #device xl # 3Com 3c90x (``Boomerang'', ``Cyclone'') > # > ## ISA Ethernet NICs. > ## 'device ed' requires 'device miibus' > device ed0 > device ed1 at isa? port 0x280 irq 3 iomem 0xd8000 > #device ex > #device ep > #device fe0 at isa? port 0x300 > ## Xircom Ethernet > #device xe > ## PRISM I IEEE 802.11b wireless NIC. > #device awi > ## WaveLAN/IEEE 802.11 wireless NICs. Note: the WaveLAN/IEEE really > ## exists only as a PCMCIA device, so there is no ISA attachment needed > ## and resources will always be dynamically assigned by the pccard code. > #device wi > ## Aironet 4500/4800 802.11 wireless NICs. Note: the declaration below will > ## work for PCMCIA and PCI cards, as well as ISA cards set to ISA PnP > ## mode (the factory default). If you set the switches on your ISA > ## card for a manually chosen I/O address and IRQ, you must specify > ## those parameters here. > #device an > ## The probe order of these is presently determined by i386/isa/isa_compat.c. > #device ie0 at isa? port 0x300 irq 10 iomem 0xd0000 > ##device le0 at isa? port 0x300 irq 5 iomem 0xd0000 > #device lnc0 at isa? port 0x280 irq 10 drq 0 > #device cs0 at isa? port 0x300 > #device sn0 at isa? port 0x300 irq 10 > # > ## Pseudo devices - the number indicates how many units to allocate. > pseudo-device loop # Network loopback > pseudo-device ether # Ethernet support > #pseudo-device sl 1 # Kernel SLIP > #pseudo-device ppp 1 # Kernel PPP > pseudo-device tun # Packet tunnel. > pseudo-device pty # Pseudo-ttys (telnet etc) > #pseudo-device md # Memory "disks" > pseudo-device gif # IPv6 and IPv4 tunneling > pseudo-device faith 1 # IPv6-to-IPv4 relaying (translation) > > # The `bpf' pseudo-device enables the Berkeley Packet Filter. > # Be aware of the administrative consequences of enabling this! > pseudo-device bpf #Berkeley packet filter > > # USB support > #device uhci # UHCI PCI->USB interface > #device ohci # OHCI PCI->USB interface > #device usb # USB Bus (required) > #device ugen # Generic > #device uhid # "Human Interface Devices" > #device ukbd # Keyboard > #device ulpt # Printer > #device umass # Disks/Mass storage - Requires scbus and da > #device ums # Mouse > #device uscanner # Scanners > ## USB Ethernet, requires mii > #device aue # ADMtek USB ethernet > #device cue # CATC USB ethernet > #device kue # Kawasaki LSI USB ethernet > > device pcm > device sbc0 at isa? port 0x220 irq 5 drq 1 flags 0x15 > options USER_LDT > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-stable" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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