Home > Articles > Operating Systems, Server > Solaris

This chapter is from the book

NFS Server

A Solaris OE system can be either an NFS server, NFS client, both, or neither. From a security perspective, the best option is to neither provide NFS services nor accept them from any other systems. To disable all client and server NFS daemons, the following startup scripts should be disabled on the system:

  • /etc/rc2.d/S73nfs.client
  • /etc/rc3.d/S15nfs.server

The Solaris OE uses a different set of startup files to enable NFS server or NFS client services.

Frequently, business requirements mandate the use of the NFS server. There are several different levels of security available in the NFS server itself. In addition, careful configuration can greatly improve security. Here is a quick overview:

  • Explicitly list hosts allowed access to NFS server directories. Do not open access to all systems.

  • Export only the lowest directory necessary.

  • Export read-only whenever possible.

  • Use strong authentication methods such as AUTH_DES or AUTH_KERB whenever possible.

The NFS server and the various mechanisms available to secure it encompass more material then can be discussed here.


The automount service manages automated NFS mounts. NFS clients may need to mount file systems from many different NFS servers. The automount service mounts file systems automatically when they are needed and unmounts them after a specific amount of idle time. A table used by this service defines the file system mount points, mount options, and the associated NFS servers. Also, in order to centralize the management of automount, the configuration tables can be stored in a name service such as NIS or NIS+. A kernel-level service (autofs) interacts with the system daemon (automountd) to manage file system mount and unmount requests. The primary automount configuration table is stored in the /etc/auto_master file.

With the Solaris OE version 2.6 release, the automount software has been, for the first time, placed in separate Solaris OE packages. By removing these packages, all automount functionality is removed from the system. The two packages that include all the automount functionality are SUNWatfsr and SUNWatfsu.

The file /etc/auto_master file determines the locations of all autofs mount points. By default, this file contains four entries:

# Master map for automounter 
net -hosts -nosuid home auto_home xfn -xfn

Ideally, automountshould be disabled because, not only does it run as a privileged daemon, but it also uses NFS and RPC. The automount system can be disabled by renaming /etc/rc2.d/S74autofs.

There are situations where the automountservice is needed for its ability to mount and unmount file systems automatically. In particular, both NIS and NIS+ environments make extensive use of auto_homeand auto_mastermaps to mount user home directories. In these situations, the configuration of the auto_master map should be carefully constructed to be as restrictive and secure as possible. This can be done by using NFS mount options and Secure RPC.

Frequently, NFS servers allow any system to mount the filesystems they export. This incorrect and all-too-common practice allows attackers to mount filesystems that may contain sensitive information. If the attacker would like to modify the contents of a particular file, they need only change their user ID or UID to that of the interesting file and modify its contents. This attack, and many other NFS-based attacks, can be avoided through the use of appropriate NFS exports and Secure RPC.

sendmail Daemon

sendmail is used on a Solaris OE system to forward and receive mail from other systems. Centralized mail servers should be used to receive mail rather than local servers. The local systems should, however, be able to generate mail and forward it to other servers.

Ideally, a more secure Mail Transport Agent (MTA) should be used instead of the MTA bundled with the Solaris OE. The sendmaildaemon, bundled with the Solaris OE, has been subjected to numerous denial of service, buffer overflow, and misconfiguration attacks. Alternative MTAs have been developed with smaller and more robust code. These other MTAs are more security conscious and, if configured properly, compromise the security of the server less than sendmail. If sendmail must be used, then the following recommendations should be followed to secure it as much as possible.

Outgoing sendmail

The sendmail daemon is not needed for email delivery to other systems. All messages that can be immediately delivered, are. Messages that cannot be immediately delivered are queued for future delivery. The sendmail daemon, if running, retries these messages again. It is recommended, for Solaris OE versions 7 and earlier, that a cron job be used to start sendmail every hour to process these undelivered messages. The following cron entry starts sendmail every hour to flush the mail queue:

0 * * * * /usr/lib/sendmail -q 

Solaris 8 OE provides a new, undocumented way to have sendmailhandle queued mail without using cron. A new default configuration file can be named /etc/ default/sendmail. In this file create the following line:


By defining the MODE to be a null string, sendmail will only process the outgoing mail queue and not accept incoming connections.

An example replacement /etc/default/sendmail file is available from the Sun BluePrints Online Tools page at http://www.sun.com/blueprints/tools, which documents the other sendmail options added to Solaris 8 OE.

Disable sendmail Daemon

If no sendmail functionality is required, it can be disabled in Solaris 2.6 OE and earlier Solaris OE releases by renaming the /etc/rc2.d/S88sendmail script. Once this script is commented out, sendmail will not be started during system startup. On systems running Solaris OE version 7 or 8, it is possible to remove all components of sendmail by removing the SUNWsndmr and SUNWsndmu packages with pkgrm.

sendmail.cf Recommendations

There is a wide variety of sendmailversions in use, and there are differences in the associated sendmail.cf configuration files. Because of this, a sample sendmail.cffile is not included with this chapter. Please refer to recommendations made at Sendmail Consortium in the Sendmail O'Reilly books and through the SunSolve OnLineSM service.

Name Service Caching (nscd)

The name service cache daemon (nscd) provides caching for name service requests. It exists to provide a performance boost to pending requests and reduce name service network traffic. The nscd maintains cache entries for databases such as passwd, group, and hosts. It does not cache the shadow password file for security reasons. All name service requests made through system library calls are routed to nscd. With the addition of IPv6 and RBAC in Solaris 8 OE, the nscd caching capability has been expanded to address additional name service databases.

It is recommended that the configuration of nscd, through the /etc/nscd.conf file, be modified to cache as little data as possible. Disabling nscd entirely, by commenting out the /etc/rc2.d/S76nscd startup script, is not recommended because there may be unexpected results. Problems have been encountered when using name services such as NIS, NIS+, and even Netscape when nscd is not running.

Tuning nscd to an appropriate minimal level can address potential security issues while maintaining a robust system configuration. In particular, the configuration should be modified so that passwd, group, and Solaris 8 OE RBAC information is not cached. Depending on what parts of nscd are disabled, there may be a performance impact on systems that have many users. The nscd -g option can be used to view the current nscd configuration on a server and is a helpful resource when tuning nscd.

A sample configuration file for an /etc/nscd.confsupporting Solaris OE versions 2.6 and 7 with passwd and group caching disabled is as follows:

enable-cache           passwd      no
enable-cache           group       no
positive-time-to-live  hosts       3600
negative-time-to-live  hosts       5
suggested-size         hosts       211
keep-hot-count         hosts       20
old-data-ok            hosts       no
check-files            hosts       yes

To disable caching of the RBAC attribute databases in the Solaris 8 OE, add the following lines to the /etc/nscd.conf file:

enable-cache exec_attr no 
enable-cache prof_attr no 
enable-cache user_attr no 

Print Services

When a Solaris OE system is installed using the End User, Development, or Entire Distribution cluster, the line printing packages are installed. Both the client and server components for print services are enabled by default on these Solaris OE installations.

The in.lpddaemon is only necessary for systems that provide network print queue services. If the system does not participate in print spooling, comment the following line in the /etc/inetd.conf file to disable this service:

printer stream tcp nowait root /usr/lib/print/in.lpd in.lpd 

Conversely, the /etc/rc2.d/S80lp script is required both for a server providing print services to other systems and a system that requires access to printers hosted by other systems. If this functionality is not required, the packages for lpshould be removed from the system, and the in.lpd entry should be removed from /etc/inetd.conf.

The three packages for lpare SUNWpsr, SUNWpsu, and SUNWlpmsg. If all lp-related functionality is to be removed, the Solstice™ Print Client should also be removed. The Solstice Print Client is contained in the SUNWpcr and SUNWpcu packages.

Solaris 8 OE adds the Solaris Print Manager (printmgr[1M]), which is a graphical printer management interface for managing both local and remote printers. The package SUNWppm should be removed if this functionality is not required.

IP Forwarding

During the startup phase of a Solaris OE system, the /etc/init.d/inetinit script evaluates the configuration of the system. It determines whether the system will be configured as a router and have ip_forwarding enabled between the different interfaces. For more information on the ip_forwarding function, refer to Chapter 2. Solaris 8 OE adds an ability to set ip_forwarding on a per-interface basis. This topic is discussed in Chapter 2.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020