Interface is down ...need help ..please

[redhat7012]

Hi,

One of our server interface is down.Device "lan1 HP PCI-X 1000Base-T Release PHNE_36236 B.11.23.0706.02" is down.

How to check the interface ?

How to bring it UP ?

Need help with COMMANDS.

Any Help is Appreciated..

Regards,

Aparna.

[Patrick Wallek]

The simplest thing to try first is:

ifconfig lan1 up

If that doesn't work you may have other issues....

[Matti_Kurkela]

To see the statistics of the lan1 interface, run:

lanadmin -g 1

 The output should look like this:

# lanadmin -g 1

                      LAN INTERFACE STATUS DISPLAY
                       Mon, Jul 30,2012  15:50:39

PPA Number                      = 1
Description                     = lan1 HP PCI-X 1000Base-T Release B.11.23.0609
Type (value)                    = ethernet-csmacd(6)
MTU Size                        = 1500
Speed                           = 1000000000
Station Address                 = 0x1122334455
Administration Status (value)   = up(1)
Operation Status (value)        = down(2)
Last Change                     = 0
Inbound Octets                  = 0
Inbound Unicast Packets         = 0
Inbound Non-Unicast Packets     = 0
Inbound Discards                = 0
Inbound Errors                  = 0
Inbound Unknown Protocols       = 0
Outbound Octets                 = 0
Outbound Unicast Packets        = 0
Outbound Non-Unicast Packets    = 0
Outbound Discards               = 1
Outbound Errors                 = 0
Outbound Queue Length           = 0
Specific                        = 655367

Ethernet-like Statistics Group

Index                           = 2
Alignment Errors                = 0
FCS Errors                      = 0
Single Collision Frames         = 0
Multiple Collision Frames       = 0
Deferred Transmissions          = 0
Late Collisions                 = 0
Excessive Collisions            = 0
Internal MAC Transmit Errors    = 0
Carrier Sense Errors            = 0
Frames Too Long                 = 0
Internal MAC Receive Errors     = 0

 Look at the "Administration Status" and "Operation Status" values. If Administration Status is "up" but Operation Status is "down", the interface may be configured but is not seeing a valid link. In that case, you must check physically:

• is the network cable connected to the server?
• has the cable been connected to the correct port?
• has the cable been damaged?
• is the other end of the cable connected to a port in a network switch?
• is the switch port in an enabled state?

The error and collision counters in the "lanadmin -g 1" output might  be informative too.

If you are not sure which physical port corresponds to lan1, run "lanscan" and note the Hardware Path. For network interfaces, it is a string of numbers separated by slashes, like "0/0/2/1/0/6/1". Then run "model" to identify your server model. Find the User Guide for your server model: there you can find a PCI slot diagram that lists the hardware paths for each PCI slot. (Or the hardware paths may be marked next to each PCI slot.)

To check the interface configuration, run "ifconfig lan1". It should display the IP address, netmask and broadcast address configured to the interface. If it says "ifconfig: no such interface" then the interface is unplumbed, i.e. it most likely is not configured at all.

(A common mistake is to configure an interface using the ifconfig command without adding the same settings to /etc/rc.config.d/netconf file. The settings made using only ifconfig will be lost when the system is rebooted: only the settings in the netconf file are persistent.)

If the interface seems to be not configured, it is important to know if this system is a part of a Serviceguard cluster or not. Run "cmversion": if it displays an error message, Serviceguard is not installed and you can configure network interfaces normally. If it displays a Serviceguard version number, Serviceguard is installed and you really should first understand its configuration before making any changes to network interface configuration.

The easiest way to configure network interfaces correctly is to use sam, a friendly menu-based interface that is useable both in a terminal session and using the X Window System.

Type "sam" to start it. If you are using a terminal session, sam will display some basic instructions: read them and press Enter.

Then select "Networking and Communications", then "Network Interface Cards". Select lan1 (on a terminal session, use the cursor keys to move to it, then press the space key). Then select Actions -> Configure (on a terminal session, press TAB to move to the menu bar, then use cursor keys to navigate to Actions -> Configure, then press Enter).

Adjust the autonegotiation/speed/duplex settings if necessary, then fill in Internet Address and Subnet Mask with the appropriate values. Then select "OK" and press Enter to make the changes take effect.