Answers to Common Network Administration Questions

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Refer to the following troubleshooting information when using the fixed mode for network administration. For information about troubleshooting network administration issues when using the reactive mode, see Answers to Common Profile-Based Network Configuration Questions. For further details, see About Network Configuration Modes in Configuring and Administering Network Components in Oracle Solaris 11.2 .

Question:

How do I determine which networking mode my system is using after an installation?

Answer:

The networking mode is determined by the profile that is activated during installation. If the DefaultFixed profile is activated, you are in the fixed mode. If the Automatic profile is activated, you are in the reactive mode. To determine which mode is currently active on your system, use the netadm list command as follows:

# netadm list

Question:

My system defaulted to reactive mode after an installation. How can I fix this problem?

Answer:

You need to switch to the fixed mode by enabling the DefaultFixed profile. Use the netadm command as follows to switch the active profile:

# netadm enable -p ncp DefaultFixed

Question:

I manually configured my system during an installation and the netadm list command shows that I am using the fixed mode, but my system's network is still not configured correctly. What should I do?

Answer:

The answer depends on which network component is not configured correctly. When in the fixed mode, you use the dladm and ipadm commands to configure the network. Given the type of configuration parameters that can be set at installation time, most likely an IP interface or address is not configured correctly. To determine which network components need to be reconfigured, start by displaying the current network configuration as follows:

# ipadm

If the IP address is incorrect, you will need to delete that address and then create the correct IP address, for example, a static IP address or a DHCP address. The following example shows how to delete the IPv6 addrconf portion of an IP configuration. In this example the IPv6 addrconf address is determined by running the ipadm command:

# ipadm
NAME              CLASS/TYPE STATE        UNDER      ADDR
lo0               loopback   ok           --         --
lo0/v4            static     ok           --         127.0.0.1/8
lo0/v6            static     ok           --         ::1/128
net0              ip         ok           --         --
net0/v4           dhcp       ok           --         10.1.1.10/24
net0/v6           addrconf   ok           --         fe80::8:20ff:fe90:10df/10
# ipadm delete-addr net2/v6
# ipadm
NAME              CLASS/TYPE STATE        UNDER      ADDR
lo0               loopback   ok           --         --
lo0/v4            static     ok           --         127.0.0.1/8
lo0/v6            static     ok           --         ::1/128
net0              ip         ok           --         --
net0/v4           dhcp       ok           --         10.1.1.10/24

Then, set just the netmask property without deleting other existing IP configuration as follows:

# ipadm set-addrprop -p prefixlen=len addrobj-name

See Chapter 3, Configuring and Administering IP Interfaces and Addresses in Oracle Solaris, in Configuring and Administering Network Components in Oracle Solaris 11.2 for complete instructions.

Question:

How do I configure a persistent default route on my system?

Answer:

Because the /etc/defaultrouter file is deprecated in Oracle Solaris 11, you can no longer manage default routes by editing this file. Also, after a fresh installation, you can no longer check this file to determine the system's default route.

Display and configure routes (default or otherwise) as follows:

Display routes that are created persistently as follows:
```
# route -p show
```
Add a persistent default route as follows:
```
# route -p add default ip-address
```
Display the currently active routes on a system as follows:
```
# netstat -rn
```

See Creating Persistent (Static) Routes in Configuring and Administering Network Components in Oracle Solaris 11.2 .

Question:

How do I display the MAC address of a system?

Answer:

Display the MAC addresses of the physical links in a system as follows:

# dladm show-phys -m

In Oracle Solaris 10, the ifconfig command is used to display similar information. Display the MAC addresses of all of the links in a system (physical and non-physical) as follows:

# dladm show-linkprop -p mac-address

Question:

I can no longer use the dladm show-dev command to display the physical links that are in my system? What command do I use now?

Answer:

Use the dladm show-phys command as follows:

# dladm show-phys
LINK              MEDIA                STATE      SPEED  DUPLEX    DEVICE
net0              Ethernet             up         0      unknown   vnet0

Question:

How do I display the mapping between link names, devices, and locations on a system?

Answer:

Use the dladm show-phys command with the –L option as follows:

# dladm show-phys -L
LINK         DEVICE        LOCATION
net0         e1000g0       MB
net1         e1000g1       MB
net2         e1000g2       MB
net3         e1000g3       MB
net4         ibp0          MB/RISER0/PCIE0/PORT1
net5         ibp1          MB/RISER0/PCIE0/PORT2
net6         eoib2         MB/RISER0/PCIE0/PORT1/cloud-nm2gw-2/1A-ETH-2
net7         eoib4         MB/RISER0/PCIE0/PORT2/cloud-nm2gw-2/1A-ETH-2

Question:

What command do I use to determine the MTU range my system supports?

Answer:

Use the ipadm show-ifprop command to determine this information, as shown in the following example. The last column displays the supported MTU ranges.

# ipadm show-ifprop -p mtu interface

Question:

What if the naming services settings on my system are lost or not configured correctly after an installation?

Answer:

If you using the fixed mode, the naming services configuration should be what you specified during the installation. In this release, naming services are configured through the Service Management Facility (SMF). See Chapter 4, Administering Naming and Directory Services on an Oracle Solaris Client, in Configuring and Administering Network Components in Oracle Solaris 11.2 for instructions on how to configure naming services and how to import naming services configuration on a client system after an installation.

Note - If you are using the reactive mode, see Creating Locations in Configuring and Administering Network Components in Oracle Solaris 11.2 .

Question:

How can I start over and reconfigure all of the network settings for my system?

Answer:

You can unconfigure and reconfigure an Oracle Solaris instance, including network settings, as follows:

# sysconfig unconfigure -g network,naming_services

Question:

What is the difference between creating a virtual LAN (VLAN) with the dladm create-vlan command and a virtual NIC (VNIC) with the dladm create-vnic -v VID ... command? Also, what are the unique features of both commands that would dictate the use of one rather than the other?

Answer:

Depending on your networking needs and what you trying to accomplish, you would use each of these features for different purposes. A VLAN is a subdivision of a LAN at the datalink layer (L2) of the network stack. VLANs enable you to divide your network into subnetworks without having to add to the physical network environment. So, the subnetworks are virtual and they share the same physical network resources. VLANs facilitate network administration by using smaller groups that are easier to maintain. VNICs are virtual network devices that use the same datalink interface as a physical network interface card (NIC). You configure VNICs over an underlying datalink. When VNICs are configured, they behave like physical NICs. Depending on the network interface that is in use, you can explicitly assign a MAC address to a VNIC other than the default address. For more information about which network administration strategies to use, see Chapter 1, Summary of Oracle Solaris Network Administration, in Strategies for Network Administration in Oracle Solaris 11.2 .