You should come away from this document with a firm understanding of
how to set up your network interfaces using the command-line interface. Also
included in this article are some basic troubleshooting hints. This document
does not cover hardware.
Requirements
To make the most of this article you need a solid grasp of the Solaris
Operating System. You should also have at least a basic understanding of
TCP/IP networking and subnet masking. To use this article, you will need
to create and edit system files, and understand the boot process (in regard
to boot scripts). Root access is mandatory.
Background
At its most basic form, a network consists of two computers that connect
to each other to collaborate on a particular task. These collaborative
tasks range from simple file transfers to the complex tasks of distributed
computing or clustering.
There are two basic parts to a network: the physical medium and the network
protocol. The physical medium employed in a network varies, depending on
how you need to connect your computers, and how much you are willing to
spend. Some of the common methods used for computer connectivity include:
Token Ring -- Developed by IBM, this network type
has each computer arranged schematically as part of a circle.
10Base2 (Coaxial) -- Each computer is strung together
using thin coaxial cable with terminators attached to each end of the chain.
10(0)BaseT -- This is your standard office/home networking
technology that uses cables with wires that are twisted in pairs. A hub/switch
allows for the connection of multiple computers. Originally seen in speeds
of 10 Mb/sec (megabits per second), it now comes in a 100 Mb/sec variety.
Fiber (Gigabit) -- Instead of twisted pair cables, this
technology uses fiber-optic cables to transmit data. It can attain speeds
of 1000 Mb/sec (1 Gb/sec), but comes at high cost and requires care when
running the cables.
Wireless 802.11a - The industrial strength wireless.
It can run at speeds of 54 Mb/sec, but at very limited range.
Wireless 802.11b -- The current standard for home and
office wireless. It runs at speeds of approximately 10Mb/sec.
Wireless 802.11g -- Combines the speed of 802.11 with
the range of 802.11b. Backward compatible with 802.11a and 802.11b.
Even if two networks are using the same medium, they can be using two
completely different protocols or methods of communication. Some protocols
used in today's networks include:
TCP/IP -- The Internet standard. Each NIC is assigned
an IP address and subnet mask. These are used to determine which machines
are in the local network and which require traffic to be sent through a router.
IPX/SPX -- A broadcast protocol developed by Novell.
Each NIC is assigned a unique IPX network address.
AppleTalk -- An Apple proprietary protocol. Each NIC
is assigned a network number, a node number, and a socket number. Similar
to TCP/IP in its configuration and routing abilities.
Verify Hardware Install
Our scenario assumes a second NIC is being installed into a previously
configured networked system. Before installing the new hardware, save the
current system configuration by running prtconf -vD. The output
of this command can be extensive on larger systems, so it's best to direct
the output of prtconf
to a file.
After physically installing the new hardware, boot the system with the
-r option from the OK prompt. This will have the system scan
for new hardware and build the device driver directories accordingly. When
that has been completed, run prtconf -vD again and compare
its content to the previous execution's results. If a new device doesn't
show up, consult the instruction manual for that device as it may require
a new driver to be installed or some other special action specific to that
hardware. Depending on the system and what other cards are installed, you
should be able to find something like the following:
SUNW,hme, instance #0 (driver name: hme) Register Specifications: Bus Type=0xe, Address=0x8c00000, Size=0x108 Bus Type=0xe, Address=0x8c02000, Size=0x2000 Bus Type=0xe, Address=0x8c04000, Size=0x2000 Bus Type=0xe, Address=0x8c06000, Size=0x2000 Bus Type=0xe, Address=0x8c07000, Size=0x20 SUNW,hme, instance #1 (driver name: hme) Register Specifications: Bus Type=0x0, Address=0x8c00000, Size=0x108 Bus Type=0x0, Address=0x8c02000, Size=0x2000 Bus Type=0x0, Address=0x8c04000, Size=0x2000 Bus Type=0x0, Address=0x8c06000, Size=0x2000 Bus Type=0x0, Address=0x8c07000, Size=0x20
The preceding example comes from an Ultra 1 workstation after the installation
of a second 100-Mb NIC on a SBus Card. The name of a NIC is the driver
abbreviation with the instance number (a consecutive number starting from
0 counting each device that uses that driver). Our devices from the preceding
prtconf output would
be known to the system as hme0 and hme1. If you cannot tell which driver
runs your hardware, consult the NIC card's manual.
The results of an ifconfig -a show us the current state of
the network devices:
lo0: flags=1000849 mtu 8232 index 1 inet 127.0.0.1 netmask ff000000 hme0: flags=1000843 mtu 1500 index 2 inet 192.168.1.100 netmask ffffff00 broadcast 192.168.1.255 ether
The built in NIC (instance #0) had previously been configured, and lo0
is an instance of the local loopback address. Since hme1 doesn't show up, it
means it has yet to be initialized and configured.
Persistent IPv4 Configuration
In order to have the system configure our NIC at boot, the first step
is to get an IP address and subnet mask. In our case, we are going to put
this second NIC into a different IP range than the original NIC. Our first
NIC is in the 192.168.1.x network, so we will put the new NIC into the
192.168.2.x network. Both of these networks have a subnet mask of 255.255.255.0.
Note: Always make sure the assigned IP is not already taken up by another
machine; to do so, use ping from a machine already configured
in that network.
Next we add a line to the /etc/hosts file for our new card:
192.168.2.100 host2.mydomain.com host2
Now, we create a file in /etc
that is named hostname. For example, our first NIC's file is
/etc/hostname.hme0. Our new device, hme1, will need
the file /etc/hostname.hme1. In this file, we will put the
name associated with the IP (as found in the /etc/hosts file).
It should be the first name in the /etc/hosts file. In our
scenario, /etc/hostname.hme1 should contain:
host2.mydomain.com
Then we edit the /etc/netmasks file for our new network:
192.168.2.0 255.255.255.0
Reboot the system, and your network card has been configured for the new
network with the proper subnet mask. You can check it by running an ifconfig
-a again:
lo0: flags=1000849 mtu 8232 index 1 inet 127.0.0.1 netmask ff000000 hme0: flags=1000843 mtu 1500 index 2 inet 192.168.1.100 netmask ffffff00 broadcast 192.168.1.255 ether hme1: flags=1000843 mtu 1500 index 3 inet 192.168.2.100 netmask ffffff00 broadcast 192.168.2.255 ether
Non-Persistence IPv4 Configuration
To configure the NIC without having to reboot (having previously installed
the hardware), you first need to initialize or plumb the network card:
ifconfig hme1 plumb
Then you configure the device:
ifconfig hme1 192.168.2.100 netmask 255.255.255.0
Now, you just bring the NIC online.
ifconfig hme1 up
Your network card is now up and running. You will still need to make the
preceding file modifications or your card will not be configured upon reboot.
IPv6 Configuration
Almost everything with IPv6 is designed to be automatic. All that is
needed is to tell the system that IPv6 is to be used, and it will handle
the rest. To configure it at boot (persistent), execute the following command:
touch /etc/hostname6
To enable IPv6 at the command line (which will be lost when the system
reboots), run the following commands:
ifconfig inet6 plumb ifconfig inet6 up
Troubleshooting
The following is a collection of tools used to troubleshoot networking
problems:
/sbin/ifconfig: The system administrator's best friend
when working with your NIC. Used to configure the network card, /sbin/ifconfig
lets you know which cards are currently recognized by the system, and their
states. Should always be your first stop when troubleshooting. An ifconfig
-a will give you information about all NIC, including IP address
(inet), subnet mask (netmask), and if run as root, the MAC address (ether).
/usr/sbin/arp: The address resolution protocol (ARP)
uses a table to keep track of the Internet-to-Ethernet translation information
(IP Address to MAC Address). arp allows you to view that table
to see what kind of information your computer has cached, as well as to
input or delete entries, in case of problems. When having DNS issues, an
arp command with the -an option will list the entire
table without resolving IP address to host names. arp is one way to get the MAC
address of the NIC answering for a host. This is done by running arp against the host name or
IP Address of the target: arp host.domain.com. However, this only works if the machine being polled
is in the same network as the machine doing the polling.
/bin/netstat: This very useful
tool displays the contents of various network-related tables. While a once-over
of the man pages is the best way to become familiar with this tool, here
is a quick cheat sheet for basic use:
Port/Socket information can be had with a netstat
-a. This is a good way to tell what remote systems are attaching
to what ports, in case you have network daemons that are locking up or if
you are wondering what computers are browsing your web server.
Most administrators check current system routing tables
with netstat -rn. The n option should almost
always be used when troubleshooting network issues, since DNS lookups for
IP-to-Hostname lookups are not local services. The entry to double check
is your "default" destination, since this is the system's default router
or gateway.
Statistics on each NIC are shown with a netstat
-I, which is often used in homemade monitoring scripts.
/usr/sbin/snoop: A packet-monitoring tool that shows
what is currently going on in the local network. Good for finding malfunctioning
NICs flooding the network or for ensuring that DHCP is working properly.
Before you configure a NIC, you can run snoop to verify that you are seeing
packets flowing through your NIC that is, the cable/NIC/switch port are
working), and the IP addresses of those packets are consistent with what
is expected for the NIC's new network. This tool should be used with caution:
Some company policies forbid the use of network monitoring tools that capture
packets if they are not intended for the machine running snoop. Also, it
is not recommended that you run snoop in verbose display-to-screen mode
when logged on to a machine remotely.
Where to Go Next
Networking can be simple and complicated at the same time. The first
stop with any UNIX application is the man pages. Next, I would suggest you
visit the Solaris Manuals online at the Sun Product Documentation site (docs.sun.com). Lastly, I would recommend
you check out the Sun Managers mailing
list.
Comments (latest comments first)
Discuss and comment on this resource in the BigAdmin Wiki
Unless otherwise licensed, code in all technical manuals herein (including articles, FAQs, samples) is provided under this License.
Print-friendly Version
