The `dladm` Command

The dladm command was introduced in Oracle Solaris 10 update releases. The full implementation of the GLDv3 driver configuration framework in the current release has expands the capabilities of the command. The framework enhances configuration of NIC drivers as follows:

Only a single command interface, the dladm command, is needed to configure network driver properties.
A uniform syntax is used regardless of the properties: dladm subcommand properties datalink.
Use of the dladm command applies to both public and private properties of the driver.
Using the dladm command on a specific driver does not disrupt network connections of other NICs of similar types. Thus, you can configure datalink properties dynamically.
Datalink configuration settings are stored in a dladm repository and persist even after you reboot the system.

To avail of the advantages previously listed when you configure datalinks, you should use dladm as the configuration tool instead of the customary tools in previous releases, such as the ndd command.

To administer datalinks, you use the following dladm subcommands:

dladm rename-link changes the name of a datalink.
dladm show-link displays existing datalinks in the system.
dladm show-phys displays physical attributes of datalinks.
dladm delete-phys deletes a datalink.
dladm show-linkprop displays the properties that are associated with the datalink.
dladm set-linkprop sets specified datalink properties.
dladm reset-linkprop restores properties to their default settings.
dladm show-ether displays Ethernet parameter settings of a datalink.

The dladm command is also used to perform other types of link administration, such as the following:

Configuring bridges. See Chapter 10, Administering Bridges
Configuring link aggregations. See Chapter 11, Administering Link Aggregations
Configuring VLANs. See Chapter 12, Administering VLANs
Configuring tunnels. See Chapter 7, Configuring IP Tunnels, in System Administration Guide: IP Services.

For more information about these commands, see the dladm(1M) man page.

The following procedures show how to use the dladm command to configure datalinks. In most cases, datalink configuration is a part of the configuration of an IP interface over that link. Thus, where applicable, the procedures include IP interface configuration steps with the ipadm command. However, IP interface configuration and the ipadm command are discussed in further detail in Chapter 8, Configuring an IP Interface.

How to Rename a Datalink

Use this procedure if you want to change a datalink name, for example, to assign a meaningful name that would easily identify the link's role within your network setup.

Before You Begin

Make sure that you have studied and prepared for other steps you need to perform on associated configurations that might be affected by the change of link names. For more information, see Working With Flexible Link Names.

Become an administrator.
For more information, see How to Obtain Administrative Rights in System Administration Guide: Security Services.
If an IP interface is configured over the datalink, remove the IP interface.
```
# ipadm delete-if interface
```
Change the link's current link name.
```
# dladm rename-link old-linkname new-linkname
```
old-linkname

Refers to the current name of the datalink. By default, the link name is hardware-based, such as bge0.

new-linkname

Refers to any name that you want to assign to the datalink. For rules for assigning link names, refer to Rules for Valid Link Names. See also Working With Flexible Link Names for further information about renaming datalinks.

If you do not want the new link name to persist across a system reboot, then use the -t option immediately after the subcommand. The option renames a link temporarily. The original link name reverts when the system is rebooted.

Note - You can use dladm rename-link to transfer link configurations from one datalink to another. For an example, see How to Replace a Network Interface Card With Dynamic Reconfiguration. When you rename a link for this purpose, make sure that the link that is inheriting the configuration does not have any prior existing configurations. Otherwise, the transfer fails.

Example 7-1 Changing a Link Name

The following example shows how a link name is changed from a hardware-based name to a customized name.

# dladm rename-link bge0 net0

How to Display Information About Physical Attributes of Datalinks

This procedure lists the steps to display information about the physical attributes of a system's datalinks.

Become an administrator.
For more information, see How to Obtain Administrative Rights in System Administration Guide: Security Services.
Display information about physical attributes of datalinks currently on the system.
```
# dladm show-phys -P
```
You can use the -P with this command to also display datalinks that are flagged as unavailable. A datalink becomes unavailable if its associated hardware has been removed. Without the -P option, the command displays only available datalinks.
To view the /devices path of the datalinks, use the -v option.

Example 7-2 Displaying Available Datalinks

In the following example, the -P option includes the FLAGS column where unavailable links are indicated. The r flag for the datalink net0 indicates the hardware that is associated with the link (nge) has been removed.

# dladm show-phys -P
LINK        MEDIA          STATE     SPEED     DUPLEX     DEVICE   FLAGS
subitops1   Ethernet       up        100Mb     full       qfe3     -----
ibd0        Infiniband     down      0Mb       --         ibd0     -----
subitops0   Ethernet       up        100Mb     full       bge0     -----
net0        Ethernet       --        0Mb       --         nge0     r----

The following example shows the output that is generated when you use the -v option.

# dladm show-phys -v
LINK     PATH
net2     /pci@1f,700000/network@2
ibd3     /pci@1d,700000/network@2
bge3     /pci@1f,700000/network@2,1

How to Display Datalink Information

This procedure displays the status of available links.

Become an administrator.
For more information, see How to Obtain Administrative Rights in System Administration Guide: Security Services.
Display link information.
```
# dladm show-link
```

Example 7-3 Displaying Available Links

The following example shows persistent and available links on the system.

# dladm show-link -P
LINK        CLASS     BRIDGE     OVER
subitops1   phys      --         --
ibd0        phys      --         --
bge0        phys      --         --

The -P option also displays any existing persistent but unavailable links. A persistent link becomes unavailable if the link is temporarily deleted. A link also becomes unavailable if the associated hardware has been removed.

How to Delete a Datalink

This procedure deletes link configurations that are associated with NICs. If you detach a NIC without intending to replace it, then you can delete the link configuration that is associated with that NIC. After you complete this procedure, the link name can be reused.

Become an administrator.
For more information, see How to Obtain Administrative Rights in System Administration Guide: Security Services.
Display the datalinks on the system including those links whose hardware have been removed.
To include information about removed hardware, use the -P option.
```
# dladm show-phys -P
```
Remove the link configuration of the removed hardware that you do not intend to replace.
```
# dladm delete-phys link
```

Example 7-4 Deleting a Datalink

In the following example, the r flag for net0 indicates that the link's associated hardware (ce) has been removed. Therefore, you can also remove the link net0 and then reassign the name to a new datalink.

# dladm show-phys -P
LINK        DEVICE     MEDIA        FLAGS
mylink0     nge0       Ethernet     -----
bge0        bge0       Ethernet     -----
net0        e1000g0    Ethernet     r----

# dladm delete-phys net0

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The dladm Command