originally posted at https://cloud1.arc.nasa.gov/success/network.lan.hints.sunos41.html


Network Config hints for SunOS 4.1.x


Setting up SunOS 4.1.x systems for use on a particular LAN can be done in a variety of ways. The following are suggestions and hints of things to check. But these suggestions may not be the only way, or the best way, to set up your system to operate on the SUCCESS LAN at Salina. Consult your local SunOS system expert for things that may be peculiar to your system.

E.g. the way the ifconfig command is used in the /etc/rc.boot and /etc/rc.local files to configure the ethernet interface has been observed to be different on different systems.

IMPORTANT: Whenever making a change to a system file, always make a copy of the original version of the file that was working before you began reconfiguration for the SUCCESS LAN.

In the following suggestions and hints, assume that your assigned fully-qualified hostname for your machine on the Salina SUCCESS LAN is "myhost.success.espo.nasa.gov", and your assigned IP address is Consult the table of assigned hostnames and IP addresses to find your actual unique values for these two items and use them. The other configuration parameters for the SUCCESS LAN are shared by all hosts. They are:


  Broadcast IP address:

  Gateway IP address:

  DNS Nameserver hosts:


Put your fully qualified SUCCESS LAN hostname in /etc/hostname.le0. If you have an Intel ethernet chip in your Sun rather than the Lance chip, then use /etc/hostname.ie0. E.g. the following single line would be in /etc/hostname.le0



Minimally put your SUCCESS LAN hostname and its IP address in your /etc/hosts file. E.g.    myhost.success.espo.nasa.gov   myhost  loghost

Dynamic hostname to IP address lookup service

If dynamic hostname-to-IP-address lookup service using the Ames name servers is desired, check that the BIND resolver version of /lib/libc.so.n.m is active on the system. (n and m are integers indicating the latest release of the shared library). To check if BIND resolver code is in the library, type:

  nm /lib/libc.so.n.m | grep 'res_'

If "res_" routine names appear, then the shared library is probably a BIND resolver library, and queries for hostnames from applications to routines in this library will result in corresponding IP addresses being fetched from the in.named daemon.

Applications such as ftp, rlogin, rcp, telnet, etc must be dynamically linked to the shared library /lib/libc.so.n.m to be able to use the BIND resolver service with the in.named daemon. This can be checked with the ldd command, e.g.

  ldd /usr/ucb/ftp 

Note that the default rcp executable that is shipped with SunOS 4.1.x systems is usually a statically linked version of rcp. The other network applications are usually dynamically linked.

Static hostname to IP address lookup service

If static hostname-to-IP-address lookup is to be used via the /etc/hosts file, ensure the in.named daemon is not started at boot time, usually in the /etc/rc.local file. Static hostname-to-IP-address lookup is handled in the usual way by placing IP-address vs hostname pairs in the /etc/hosts file. A sample list of local SUCCESS LAN unix /etc/hosts entries are on the SUCCESS web pages under the "computer network" link.


Insert the following line in /etc/netmasks to define the netmask for the SUCCESS LAN. The netmask is all 1 bits in the 1st 24 bits of the IP address, and all 0 bits in the last 8 bits of the IP address.

/etc/rc.boot and /etc/rc.local

Find the one or more "ifconfig" commands in /etc/rc.boot and /etc/rc.local. These commands configure your ethernet hardware interface, associate a hostname with an IP address for an interface, define a broadcast address, define a netmask, and set other options.

Locate the ifconfig command(s) that reference the netmask option, and ensure that they use either:

  netmask +


  netmask ''

Locate the ifconfig command(s) that reference the broadcast option, and ensure that they use:

 broadcast ''

One of the ifconfig commands should have a trailers link level encapsualtion option disabled. E.g.


One of the ifconfig commands should associate the hostname with the ethernet interface. This is sometimes done by using the contents of /etc/hostname.le0, and sometimes by explicitly putting the hostname in the ifconfig command. If the explicit hostname method is used, ensure that your complete SUCCESS LAN hostname appears.

These ifconfig options might all be set in one ifconfig command, or may be in several ifconfig commands, some in /etc/rc.boot &/or /etc/rc.local.

The ifconfig commands can be the most confusing parts of the configuration for operation on a new LAN. But since they are important to proper operation, be sure to consult your local expert if you have questions about them.


Find the line in one of your /etc/rc.* files, usually /etc/rc.local, where in.routed is started. Ensure that it will run in cache routing quiet mode. I.e.:

  /usr/etc/in.routed -q

Remove other static "route" commands in rc.*, and ensure that file /etc/defautrouter does not exist. Our default route on the SUCCESS LAN (for packets not going to another machine on the LAN) will be our local router gateway to the Internet. That router's IP address will be The above in.routed command should set things up to find this default address, and to suppress the unnecessary broadcast of each host's routing tables to all the other hosts on the LAN.


Make /etc/defaultdomain an empty file.


Set the local domain name for email to the one we are using for the SUCCESS LAN by finding the line within /etc/sendmail.cf that begins with "DD", and change that line to:


If you have a /etc/sendmail.cw file, put your SUCCESS LAN hostname in it. E.g.

myhost.success.espo.nasa.gov myhost


It is probably best to let the root nameservers find the primary or secondary nameserver for the SUCCESS LAN automatically if you are are running dynamic DNS BIND service for mapping hostnames to IP addresses. In this case, simply remove the /etc/resolv.conf file.

However, some systems are set up to explicitly refer to one or more remote nameservers in the /etc/resolv.conf file. The following nameservers could be listed in the /etc/resolv.conf file for the SUCCESS LAN:

domain      success.espo.nasa.gov

The first is a nameserver cloud4.success.espo.nasa.gov that is expected to be operating on the SUCCESS LAN for fast nameserver access. The second is the machine cloud1.arc.nasa.gov at NASA Ames that is expected to maintain the latest hostname vs IP addresses for the SUCCESS LAN. The primary cloud1 machine at Ames will download its hostname vs IP address table to the secondary cloud4 machine on the Salina LAN.

If you are using the /etc/resolv.conf method of pointing at BIND nameservers, then it is best to not start your caching nameserver daemon in.named.

If you are using static name to IP lookup in your /etc/hosts file, then do not start in.named, and remove /etc/resolv.conf.


The SUCCESS LAN will be operating in the Midwest timezone. To have commands such as "date" and "ls -l" use local time, you can set the local time zone by:

  cd /usr/share/lib/zoneinfo/
  cp localtime localtime.save
  cp CST6CDT localtime

Some systems are set up to define the time zone with the TZ environment variable on a per user basis. If that works better for you, have users define TZ to CST6CDT, probably in their .login (csh or tcsh) or .profile (sh) files.

E.g. in the csh or tcsh shells:

  setenv TZ "CST6CDT"
or in the sh shell:
  export TZ

Other things to check

If your machine is going to be a print server, &/or will be spooling to print queues on other machines using the Berkeley network printing system, check your /etc/hosts.lpd and /etc/printcap files to ensure they contain the appropriate names of machines on the LAN.

Some machines may have entries in their cron table or license manager software's database file(s) that are specific to the LAN on which they are operating. You may want to check these for proper setup on the Salina LAN.