RHEL 5.3 having intermittent network disconnects issues.

RHEL 5.3 having intermittent network disconnects issues.

Article Summary: This article provides information on RHEL 5.3 having intermittent network disconnects issues.


  • Red Hat Enterprise Linux 5.3 and newer
  • Network Interface Cards (NIC) using the bnx2 driver including:
    • Broadcom Corporation NetXtreme II BCM5709S Gigabit Ethernet


  • In certain situations under heavy loads, the network interface card can stop accepting packets from remote devices.
  • This problem has been reported on Red Hat Enterprise Linux 5.3 (RHEL 5.3) and newer when using a Broadcom NetXtreme 5709 network interface card.

Diagnostic Steps

  • var\log\messages shows entries similar to:
    • Jul 28 12:03:51 server01 kernel: bnx2: eth2: using MSIX

    • Jul 28 12:03:51 server01 kernel: ADDRCONF(NETDEV_UP): eth2: link is not ready

    • Jul 28 12:03:53 server01: bnx2: eth2 NIC Copper Link is Up, 1000 Mbps full duplex, receive & transmit flow control ON

    • Jul 28 12:03:53 fserver01 kernel: ADDRCONF(NETDEV_CHANGE): eth2: link becomes ready

  • Check if packets sent to the NIC are dropped by repeatedly using this command:
    # ethtool -S eth0 | grep rx_fw_discards
    • Each time this command is executed, the value returned should increase from the previous run as a result of remote devices attempting to communicate with the NIC in question. The numbers should increase similar to this:
    • rx_fw_discards: 53843

    • rx_fw_discards: 55467

    • rx_fw_discards: 57071

  • Confirm that the number of interrupts processed does not increase on the IRQs assigned to the NIC by repeatedly using this command:
  • # grep eth0 /proc/interrupts
    • (Modify "eth0" with the name of the interface where trouble is suspected.)
    • The command should be run while remote devices are attempting to transmit to the failing system. Normally, each counter for the interrupts listed for that interface (e.g. eth0) should increase as packets are received from remote devices.


  • Red Hat has released kernel-2.6.18-194.3.1.el5 which will address this issue in RHEL 5. It can be downloaded from the following link: Important: kernel security and bug fix update
  • If upgrading the kernel is not an option, review the following workaround:
    • Disable MSI-X in the bnx2 driver and reboot the server. To do this, add the following line to /etc/modprobe.conf
      options bnx2 disable_msi=1
  • Disable C-States in BIOS.

Reference: Why does the Broadcom NetXtreme 5709 NIC stop receiving packets intermittently on RHEL 5.3 and newer? 

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Article ID: SLN266054

Last Date Modified: 09/12/2013 12:00 AM

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