What I'm going to explain is happening on two different servers with same OS, same hardware and same hardware upgrade. IMHO I think may be a driver error is going on, but don't know how to figure it out.
I'm having some strange troubles with this server which is based on a supermicro motherboard.
The server runs red hat linux.
The server "hangs" when I do "ifconfig eth2 down" , also with eth3.
This eth2 and eht3 belong to a new pci card added last week.
Eth0 and eth1 are integrated on the motherboard and they work with igb driver. Eth2 and eth3 are the new ones on a pci and depends on e1000e driver.
Eth0 is configured as follows and is working fine.
Eth1 is configured as follows and is working fine.
Eth2 and eth3 have been configured in many ways, but to figure out which can be the problem I've connected them(one by one) to a network with dhcp, then call dhcpclient eth2 or eth3, and when ifconfig down the computer still hangs. So IMHO the configuration does not matter.
The modprobe.conf file looks as follows:
alias eth0 igb
alias eth1 igb
alias scsi_hostadapter ahci
install vtune_drv /opt/intel/vtune/mknod_vtune.sh
remove vtune_drv /opt/intel/vtune/rmnod_vtune.sh
alias char-major-10-111 mdm
igb and e1000e modules are loaded and I can see them with lsmod. If anyone would like to take a look to the lsmod output can do it here --> http://pastebin.com/jJ7kk8mn
what lspci shows on ehternet is at follows (2 first eth are eth0 and eth1)
01:00.0 Ethernet controller: Intel Corporation 82576 Gigabit Network Connection (rev 01)
01:00.1 Ethernet controller: Intel Corporation 82576 Gigabit Network Connection (rev 01)
03:00.0 Ethernet controller: Intel Corporation 82571EB Gigabit Ethernet Controller (rev 06)
03:00.1 Ethernet controller: Intel Corporation 82571EB Gigabit Ethernet Controller (rev 06)
lspci output can be checked here --> http://pastebin.com/j94fWUPw
also the lspci with verbose can be seen here --> http://pastebin.com/HRdMttzm
The boot.log does not show any interesting information.
/var/log/messages --> http://pastebin.com/wLQnaxru
/var/log/kernel/info --> http://pastebin.com/3KzF9Hhu
And I don't know what else can be useful to be able to help me , but I will be willing to help on being helped. :)
Many thanks to all who read all this long post, sincerely.