在断网时候通过ipmi查看系统，发现系统正常运行，只是不能连接网络。进入系统日志找来找去，发下一下报错：

May 28 13:55:00 localhost kernel: ------------[ cut here ]------------May 28 13:55:00 localhost kernel: WARNING:at net/sched/sch_generic.c:261 dev_watchdog+0x26b/0x280() (Not tainted)May 28 13:55:00 localhost kernel: Hardware name: X9SCL/X9SCMMay 28 13:55:00 localhost kernel: NETDEV WATCHDOG: eth0 (e1000e): transmit queue 0 timed outMay 28 13:55:00 localhost kernel: Modules linked in: autofs4 cpufreq_ondemand acpi_cpufreq freq_table mperf ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables ipv6 iTCO_wdt iTCO_vendor_support microcode serio_raw e1000e ptp pps_core sg i2c_i801 i2c_core lpc_ich mfd_core shpchp ext4 jbd2 mbcache sd_mod crc_t10dif ahci video output dm_mirror dm_region_hash dm_log dm_mod [last unloaded: scsi_wait_scan]May 28 13:55:00 localhost kernel: Pid: 20176, comm: 64a Not tainted 2.6.32-431.el6.x86_64 #1May 28 13:55:00 localhost kernel: Call Trace:May 28 13:55:00 localhost kernel:   [] ? warn_slowpath_common+0x87/0xc0May 28 13:55:00 localhost kernel: [] ? warn_slowpath_fmt+0x46/0x50May 28 13:55:00 localhost kernel: [] ? dev_watchdog+0x26b/0x280May 28 13:55:00 localhost kernel: [] ? ghes_poll_func+0x0/0x30May 28 13:55:00 localhost kernel: [] ? add_timer+0x18/0x30May 28 13:55:00 localhost kernel: [] ? dev_watchdog+0x0/0x280May 28 13:55:00 localhost kernel: [] ? run_timer_softirq+0x197/0x340May 28 13:55:00 localhost kernel: [] ? tick_dev_program_event+0x65/0xc0May 28 13:55:00 localhost kernel: [] ? __do_softirq+0xc1/0x1e0May 28 13:55:00 localhost kernel: [] ? tick_program_event+0x2a/0x30May 28 13:55:00 localhost kernel: [] ? call_softirq+0x1c/0x30May 28 13:55:00 localhost kernel: [] ? do_softirq+0x65/0xa0May 28 13:55:00 localhost kernel: [] ? irq_exit+0x85/0x90May 28 13:55:00 localhost kernel: [] ? smp_apic_timer_interrupt+0x4a/0x60May 28 13:55:00 localhost kernel: [] ? apic_timer_interrupt+0x13/0x20May 28 13:55:00 localhost kernel:   [] ? sk_alloc+0x7a/0x140May 28 13:55:00 localhost kernel: [] ? sk_alloc+0x6f/0x140May 28 13:55:00 localhost kernel: [] ? inet_create+0x19e/0x390May 28 13:55:00 localhost kernel: [] ? new_inode+0x72/0xb0May 28 13:55:00 localhost kernel: [] ? __sock_create+0x117/0x240May 28 13:55:00 localhost kernel: [] ? sock_create+0x30/0x40May 28 13:55:00 localhost kernel: [] ? sys_socket+0x3c/0x80May 28 13:55:00 localhost kernel: [] ? system_call_fastpath+0x16/0x1bMay 28 13:55:00 localhost kernel: ---[ end trace 6a44a642566ebafb ]---May 28 13:55:00 localhost kernel: e1000e 0000:02:00.0: eth0: Reset adapter unexpectedlyMay 28 13:55:00 localhost kernel: e1000e 0000:02:00.0: eth0: Timesync Tx Control register not set as expected

通过网上搜素，发现是网卡驱动出现了问题，网上的解决方法是更新网卡驱动。由于没有亲自测试网卡驱动，本次就通过“yum -y update”更新系统，更新网卡驱动

[root@localhost ~]# uname -aLinux localhost.localdomain 2.6.32-431.el6.x86_64 #1 SMP Fri Nov 22 03:15:09 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux[root@localhost ~]# cat /proc/versionLinux version 2.6.32-431.el6.x86_64 (mockbuild@c6b8.bsys.dev.centos.org) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-4) (GCC) ) #1 SMP Fri Nov 22 03:15:09 UTC 2013[root@localhost ~]#  lsb_release -aLSB Version:	:base-4.0-amd64:base-4.0-noarch:core-4.0-amd64:core-4.0-noarch:graphics-4.0-amd64:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-noarchDistributor ID:	CentOSDescription:	CentOS release 6.5 (Final)Release:	6.5Codename:	Final查看网卡驱动[root@localhost ~]# modinfo bnx2filename:       /lib/modules/2.6.32-431.el6.x86_64/kernel/drivers/net/bnx2.kofirmware:       bnx2/bnx2-rv2p-09ax-6.0.17.fwfirmware:       bnx2/bnx2-rv2p-09-6.0.17.fwfirmware:       bnx2/bnx2-mips-09-6.2.1b.fwfirmware:       bnx2/bnx2-rv2p-06-6.0.15.fwfirmware:       bnx2/bnx2-mips-06-6.2.3.fwversion:        2.2.3license:        GPLdescription:    Broadcom NetXtreme II BCM5706/5708/5709/5716 Driverauthor:         Michael Chan <mchan@broadcom.com>srcversion:     17D4A614D14049C677860ECalias:          pci:v000014E4d0000163Csv*sd*bc*sc*i*alias:          pci:v000014E4d0000163Bsv*sd*bc*sc*i*alias:          pci:v000014E4d0000163Asv*sd*bc*sc*i*alias:          pci:v000014E4d00001639sv*sd*bc*sc*i*alias:          pci:v000014E4d000016ACsv*sd*bc*sc*i*alias:          pci:v000014E4d000016AAsv*sd*bc*sc*i*alias:          pci:v000014E4d000016AAsv0000103Csd00003102bc*sc*i*alias:          pci:v000014E4d0000164Csv*sd*bc*sc*i*alias:          pci:v000014E4d0000164Asv*sd*bc*sc*i*alias:          pci:v000014E4d0000164Asv0000103Csd00003106bc*sc*i*alias:          pci:v000014E4d0000164Asv0000103Csd00003101bc*sc*i*depends:        vermagic:       2.6.32-431.el6.x86_64 SMP mod_unload modversions parm:           disable_msi:Disable Message Signaled Interrupt (MSI) (int)

yum -y update

reboot

[root@localhost ~]# modinfo bnx2filename:       /lib/modules/2.6.32-642.el6.x86_64/kernel/drivers/net/bnx2.kofirmware:       bnx2/bnx2-rv2p-09ax-6.0.17.fwfirmware:       bnx2/bnx2-rv2p-09-6.0.17.fwfirmware:       bnx2/bnx2-mips-09-6.2.1b.fwfirmware:       bnx2/bnx2-rv2p-06-6.0.15.fwfirmware:       bnx2/bnx2-mips-06-6.2.3.fwversion:        2.2.6license:        GPLdescription:    QLogic BCM5706/5708/5709/5716 Driverauthor:         Michael Chan <mchan@broadcom.com>srcversion:     16BA5FA9F22B085C53076ECalias:          pci:v000014E4d0000163Csv*sd*bc*sc*i*alias:          pci:v000014E4d0000163Bsv*sd*bc*sc*i*alias:          pci:v000014E4d0000163Asv*sd*bc*sc*i*alias:          pci:v000014E4d00001639sv*sd*bc*sc*i*alias:          pci:v000014E4d000016ACsv*sd*bc*sc*i*alias:          pci:v000014E4d000016AAsv*sd*bc*sc*i*alias:          pci:v000014E4d000016AAsv0000103Csd00003102bc*sc*i*alias:          pci:v000014E4d0000164Csv*sd*bc*sc*i*alias:          pci:v000014E4d0000164Asv*sd*bc*sc*i*alias:          pci:v000014E4d0000164Asv0000103Csd00003106bc*sc*i*alias:          pci:v000014E4d0000164Asv0000103Csd00003101bc*sc*i*depends:        vermagic:       2.6.32-642.el6.x86_64 SMP mod_unload modversions parm:           disable_msi:Disable Message Signaled Interrupt (MSI) (int)

系统更新了，网卡也进行了更新，下面就是看系统网卡是否正常