Possible SYN flood related to Cyclone cards on Linux?

Tue Oct 6 19:48:05 1998

Since receiving a batch of machines with 3c905b cards and using the 0.99E
version of the driver from ftp://cesdis.gsfc.nasa.gov/pub/linux/drivers/3c59x.c
on a 10 Mbs network, we've been getting a lot of messages of the form:

Oct  6 18:12:51 xxxx kernel: Warning: possible SYN flood from 111.1.111.111 on 111.1.111.222:635.  Sending cookies.

when the machine at IP address 111.1.111.111 has one of the 3c905b cards and
is trying to do some network operation with the machine at 111.1.111.222.

While dealing with the problem, both machines basically grind to a halt.
Generally, at the time this is occurring, the .111 machine is attempting to
do an automount of a filesystem on the .222 machine.  Attempting to upgrade
to the 0.99G version of the driver completely hung the .111 machine on reboot.

Other than the network card, the hardware setup of these new machines is very
close to other Linux boxes that don't have this problem.  The software setup
is just about identical (particularly with automount).  The kernel is 2.0.34.

Has anyone else seen this?

I don't know if this has any logical connection.  I'm just fishing for answers.

Thanks in advance for any suggestions,
Mike

================================================================================

Status lights on the card seem to indicate it's operating in 10 Mbs mode.

Boot-time info:

3c59x.c:v0.99E 5/12/98 Donald Becker http://cesdis.gsfc.nasa.gov/linux/drivers/vortex.html
loading device 'eth0'...
eth0: 3Com 3c905B Cyclone 100baseTx at 0x1000, 00:10:5a:1f:1b:54, IRQ 10
  8K byte-wide RAM 5:3 Rx:Tx split, autoselect/NWay Autonegotiation interface.
  Enabling bus-master transmits and whole-frame receives.

Output from vortex-diag:

> vortex-diag -a -e -m -v
vortex-diag.c:v1.05 5/22/98 Donald Becker (becker@cesdis.gsfc.nasa.gov)
Found a 3Com PCI Ethernet 3c905b rev 0 at 0x1000.
The Vortex chip may be active, so FIFO registers will not be read.
To see all register values use the '-f' flag.
Initial window 7, registers values by window:
  Window 0: 0000 0000 0000 0000 5555 00bf 0000 0000.
  Window 1: FIFO FIFO 0000 0000 0000 0000 0000 2000.
  Window 2: 1000 1f5a 541b 0000 0000 0000 000a 4000.
  Window 3: 0000 0100 05ea 0000 000a 0800 0800 6000.
  Window 4: 0000 0000 0000 0cd8 0007 88c0 0000 8000.
  Window 5: 1ffc 0000 0000 0600 0807 069e 06c6 a000.
  Window 6: 0000 0000 0000 5100 0000 6445 1628 c000.
  Window 7: 0000 0000 0000 0000 0000 0000 0000 e000.
Vortex chip registers at 0x1000
  0x1010: **FIFO** **FIFO** 00000023 00000000
  0x1020: 00000020 00000000 00080000 00000004
  0x1030: 00000000 1f02e0fe 07d2da70 00080004
 No interrupt sources are pending.
 Transceiver/media interfaces available:  100baseTx 10baseT.
 MAC settings: half-duplex.
EEPROM contents:
  0010 5a1f 1b54 9055 c51a 0036 5a51 6d50
  2979 0000 0010 5a1f 1b54 0010 0000 002a
  32a2 0000 0000 0180 0000 0000 0000 10b7
  9055 000a 0000 0000 0000 0000 0000 0000
  0009 0000 0000 0000 0000 0000 0000 0000
  0000 0000 0000 0000 0000 0000 0000 0000
  0000 0000 0000 0000 0000 0000 0000 0000
  0000 0000 0000 0000 0000 0000 0000 0000
 The word-wide EEPROM checksum is 0x0740.
Parsing the EEPROM of a 3Com Vortex/Boomerang:
 3Com Node Address 00:10:5A:1F:1B:54 (used as a unique ID only).
 OEM Station address 00:10:5A:1F:1B:54 (used as the ethernet address).
 Manufacture date (MM/DD/YY) 8/26/98, division 6, product QZ.
Options: .
  Vortex checksum is 61 (vs. 10b7),Cyclone checksum is 09 (vs. 09).
 MII PHY found at address 0, status 784d.
 MII PHY found at address 1, status 784d.
 MII PHY found at address 2, status 784d.
 MII PHY found at address 3, status 784d.
 MII PHY 0 at #0 transceiver registers:
   3000 784d 0000 0000 01e1 0000 0004 2001
   0000 0000 0000 0000 0000 0000 0000 0000
   0000 0080 00d0 0000 0000 0005 2001 0000
   0000 2040 07cf 1c11 0191 1000 0000 0000.
 MII PHY 1 at #1 transceiver registers:
   0000 0000 0000 0000 0000 0000 0000 0000
   0000 0000 0000 0000 0000 0000 0000 0000
   0000 0000 0000 0000 0000 0000 0000 0000
   0000 0000 0000 0000 0000 0000 0000 0000.
 MII PHY 2 at #2 transceiver registers:
   0000 0000 0000 0000 0000 0000 0000 0000
   0000 0000 0000 0000 0000 0000 0000 0000
   0000 0000 0000 0000 0000 0000 0000 0000
   0000 0000 0000 0000 0000 0000 0000 0000.
 MII PHY 3 at #3 transceiver registers:
   0000 0000 0000 0000 0000 0000 0000 0000
   0000 0000 0000 0000 0000 0000 0000 0000
   0000 0000 0000 0000 0000 0000 0000 0000
   0000 0000 0000 0000 0000 0000 0000 0000.
________________________________________________________________________
Michael A. Jaskowiak    Template Software    mike.jaskowiak@template.com