comp.unix.admin FAQ
comp.unix.admin FAQ, v0.9 28 Apr 1998
khockenb@stevens-tech.edu
This document is meant to serve as a general overview of comp.unix.admin
issues, and a pointer to more specific answers and FAQs. I encourage
questions, comments, and clarifications to be sent to me,
khockenb@stevens-tech.edu. Please put [FAQ] somewhere in the
"Subject:" line.
The latest text version of this FAQ can be retrieved from:
<http://attila.stevens-tech.edu/~khockenb/comp-unix-admin.faq>
There is also an html version:
<http://attila.stevens-tech.edu/~khockenb/comp-unix-admin.html>
Thanks to the SGI-faq maintainers for making their tools available
for conversion of FAQ digests to html.
Subject: 1. Table of Contents
I) Contents & Purpose
1. Table of Contents
2. Purpose of comp.unix.admin
II) Sysadmining
3. I'm a new admin, what books should I read?
4. Are there any magazines that deal with system administration?
5. What online information is there?
6. What duties does a sysadmin perform?
7. How does one enter the field/gain experience?
8. What is the ratio of admins/{users|workstations}
9. I have a job opening for a Unix Sysadmin
10. What professional/user groups exist for sysadmins?
II) Technical Issues
11. How do I remove a file that starts with a "-"?
12. How do I undelete a file in Unix?
13. Where can I find automated pager software?
14. How do I disable a user account?
15. What can I do to secure my system?
16. What are some useful sysadmin utilities I might want to install?
17. Where can I get menu software for novice users?
18. How can I mirror files via FTP/HTTP? / How can I automate FTP?
19. How do I set up multiple IP addresses on a single interface?
20. I'm looking to set up a firewall
21. I'm thinking of starting an Internet Service Provider
22. I have OS <xxx>, how do I ...?
23. Help! Root doesn't have a valid password entry/
We lost the root password!
24. How do I determine what process owns a socket/
what files are open by which processes?
25. What alternatives are there to sendmail?
26. How can I print to/from Windows95/NT and my Unix box?
27. What software can I use to set up mailing lists?
28. How can I kick off inactive users?
29. How can I change passwords from a script?
30. Disclaimer and Copyright information
Subject: 2. Purpose of comp.unix.admin
comp.unix.admin is a newsgroup for the discussion of administration of
UNIX machines, generally for those issues of UNIX administration that
are vendor-independent. For more vendor-specific UNIX questions, see
section 22 for a list of appropriate newsgroups.
Subject: 3. I'm a new admin, what books should I read?
There are two main sysadmin "bibles"; some people prefer one or the
other, many people own both. They are:
UNIX System Administration Handbook 2nd edition
Evi Nemeth, et.al.
ISBN 0-13-151051-7
Published by Prentice Hall <http://www.prenhall.com/>
OS Coverage: BSDI, HPUX, IRIX, OSF/1, Solaris, SunOS
Essential System Administration, 2nd edition
AEleen Frisch
ISBN: 1-56592-127-5
Published by O'Reilly & Associates <http://www.ora.com/>
OS Coverage: Sun OS 4.1, Solaris 2.3, AIX 4.1, Linux 1.1, Digital UNIX
OSF/1, SCO UNIX v. 3, HP/UX v. 9 and 10, and IRIX v. 6.
Either of these will be a great help in getting you started in Unix system
administration. Get your boss to buy you both, and you won't regret it.
For more in-depth information on specific topics, O'Reilly makes a
whole zoo of worthwhile books.
Some of the more worthwhile O'Reilly titles for a sysadmin include:
DNS and BIND
Learning Perl
Managing Internet Information Services
Managing NFS and NIS
Practical Unix & Internet Security
Programming Perl
sendmail
TCP/IP Network Administration
System Performance Tuning
For a complete list of O'Reilly volumes, see <http://www.ora.com/>
Other useful books for a sysadmin include:
Internetworking with TCP/IP, Volume 1
Douglas Comer
Publisher: Prentice Hall
ISBN: 0-13-468505-9
Advanced Programming in the UNIX Environment
W. Richard Stevens
Publisher: Addison-Wesley
ISBN: 0-201-56317-7
Firewalls and Internet Security
Bill Cheswick and Steve Bellovin
Publisher: Addison-Wesley
ISBN: 0-201-63357-4
The comp.unix.questions FAQ
<ftp://rtfm.mit.edu/pub/usenet/news.answers/unix-faq/faq/> should be
read by all system administrators, especially parts 2 through 5. For
further reading, note that section 1.5 (What are some useful Unix or C
books?) has pointers to two other Unix Book lists.
SAGE, The System Administrators Guild, maintains the SAGE Sysadmin's
Bookshelf <http://www.sage.usenix.org/sage/sysadmins/books/booklist.html>,
a list of books useful to a sysadmin.
Subject: 4. Are there any magazines that deal with system administration?
Linux Journal <http://www.ssc.com/lj/>
;login <http://www.usenix.org/>
SunExpert <http://www.netline.com/sunex/>
Performance Computing (Unix Review) <http://www.performancecomputing.com/>
Sys Admin
PO Box 59170
Boulder CO 80322-9170
1-800-365-2210; 303-678-0439; FAX 303-661-1885.
email:sasub@rdpub.com
<http://www.samag.com/>
OpenComputing
Open Computing Subscriptions Dept
PO Box 571
Hightstown NJ 08520
1-800-525-5003
[This section could use some more listings, and perhaps a mini-review as
to its usefulness to a sysadmin. -Kurt]
Subject: 5. What online information is there?
Other newsgroups of interest:
comp.protocols.tcp-ip.domains, comp.security.announce,
comp.security.firewalls, com.security.unix, comp.unix.questions,
news.software.b
Other FAQs posted regularly to this newsgroup:
(The first 5 are all available from <ftp://ftp.iss.net/pub/faq/>)
anonymous-ftp FAQ
compromise FAQ
security-patches FAQ
sniffers FAQ
vendor-contacts FAQ
<ftp://iss.net/pub/>
ISO 8859-1 National Character Set FAQ
<ftp://rtfm.mit.edu/pub/usenet/news.answers/internationalization/iso-8859-1-charset>
Uninterruptible Power Source FAQ
<ftp://rtfm.mit.edu/pub/usenet/news.answers/UPS-faq>
Related FAQs
The comp.unix.questions FAQ
<ftp://rtfm.mit.edu/pub/usenet/news.answers/unix-faq/faq/>
Some web sites:
THE UNIX REFERENCE DESK
<http://www.geek-girl.com/unix.html>
[Excellent resource. Much more to offer than this FAQ.]
Computer Security Technology Center (CSTC)
<http://ciac.llnl.gov/cstc/>
CIAC Security Web Site
<http://ciac.llnl.gov/ciac/>
INTRODUCTION TO UNIX SYSTEM ADMINISTRATION
by Frank G. Fiamingo
<http://sunos-wks.acs.ohio-state.edu/sysadm_course/sysadm.html>
DNS RESOURCES DIRECTORY
<http://www.dns.net/dnsrd/>
Internet Tools Summary
<http://www.december.com/net/tools/index.html>
Ethernet: Access to 10 and 100-Mbps Ethernet/IEEE 802.3 Information
<http://wwwhost.ots.utexas.edu/ethernet/ethernet-home.html>
Unix Guru Universe
<http://www.ugu.com/>
Cameron Laird's personal notes on system administration
<http://starbase.neosoft.com/~claird/comp.unix.admin/admin.html>
Unix System Administrator's Resources
<http://www.stokely.com/stokely/unix.sysadm.resources/index.html>
See also section 22.
Subject: 6. What duties does a sysadmin perform?
Duties can be quite site-specific. Typical things that a sysadmin does,
in the quest to keep things running smoothly, include:
ensuring backups are being made timely and correctly
closing security holes
watching the system logs for problems
keeping the software up-to-date
keeping current with his knowledge of the software
writing small programs and scripts
maintaining the network hardware and software
keeping track of resource usage (so you don't run out of disk space,
ram, cpu cycles, or network bandwidth at a crucial moment)
evaluating and recommending hardware and software
doing field repairs on equipment (replacing disks, boards, etc.)
routine maintenance (cleaning tape drives, replacing toner cartridges)
pull wire for new workstations
account creation and deletion
user training
writing documentation
answering user questions
I've probably missed dozens of other things. It's been said that if a
sysadmin does his job perfectly, he's the fellow that people wonder what
he does and why the company needs him, until he goes on vacation. :-)
It *can* be a thankless job, since people tend to notice you only when
there's a problem.
Do I need to know "C"? is question that sometimes crops up in these
discussions. The answer is "probably". While you can do large portions
of Unix administration without touching C (especially if you can write
shell/awk/sed or perl programs), sooner or later you will be hit with a
C program you need to compile, install, or port. At that time, a
working knowledge of C comes in handy. C also helps when you need to
make modifications in the utilities you just ported or installed.
SAGE has a list of job descriptions for different levels of sysadmins. See
<http://www.sage.usenix.org/sage/jobs/jobs-descriptions.html>.
Subject: 7. How does one enter the field/gain experience?
Some people find themselves thrust into system administration, when their
company buys a new piece of hardware and they're elected to run it. Others
go out job hunting, specifically to be system administrators.
What do employers want? Someone who is motivated, willing to work
whatever hours it takes, and able learn on the fly. System
administration covers a broad range of topics, and varies from place to
place; as a starting or junior sysadmin, you probably won't be expected
to know everything to start with, but you are expected to come up to
speed on the major things your company needs in a few weeks time, and
fill in the rest over time.
The best way to learn system administration is to *do* system
administration. Five years ago, this could be expensive, but in these
days of commodity hardware and free, source available Unixes, it's a
bit easier. Your best bet is to install one (or more!) of the free Unix
clones: Linux <http://www.ssc.com/linux/>, FreeBSD <http://www.freebsd.org/>,
NetBSD <http://www.netbsd.org/>, or OpenBSD <http://www.openbsd/org/>.
Also, SCO <http://www.sco.com/> is now offering near free 2-user,
no-commercial-use copies of SCO OpenServer. You can't ftp it, but you can
order it for media+shipping costs, and install it on multiple machines.
Which is best? The answer is "all of them". Unless you're going to
become a sysadmin at a place with homogeneous Unix servers, you're best
bet is learning as much as you can about all Unix versions you can get
your hands on.
Subject: 8. What is the ratio of admins/{users|workstations}
Every once in a while, this question gets asked, and the answer is "it
varies". Keeping 200 identical workstations functional is easier than
trying to do the same to 50 workstations running eight different OSes,
and admin'ing systems for a group of computational physicists is
different than admin'ing for a horde of undergraduates, though the
computational hardware may be identical.
There's also the issue of who you count as an administrator: the
operations staff that does backups and hands out printer output? The
person(s) who do account creation? The helpdesk staff?
Ideally, anyone who has root access is an admin, but, due to political
reasons or limited staffing, this may not be possible. Conversely, there
may be people who perform some admin duties, but don't have (or need)
root access.
Sherwood Botsford <sherwood@space.ualberta.ca> states:
"My rule of thumb:
Unit counting:
1 unit for each 50 users.
1 unit for each make of OS (2 for Windows NT, 1.5 for WfWg)
1 unit for each 10 boxes.
1 unit if you have tight coupling. (Lots of NFS cross mounts.)
1/2 to 1 unit for major subsystems that are set up network wide
instead of machine wide. E.g. newsspool, httpd, DNS, mail, printing,
SAMBA.
1/2 unit for each additional subnet or segment if multisegmented
LAN.
Junior admins can handle 4 units. A really good experienced
admin can hack 8-12 units."
Tom Limoncelli <tal@plts.org> adds "In a research environment, 50:1 is
appropriate since the users need more customization. In a University
environment, 200:1 is appropriate since 90% of the users should fit into
a cookie-cutter mold of what they are supposed to be doing, and there
is usually a help-desk to handle direct support so the sysadmins can
focus on purely technical work."
Finally, Mark Verber wrote an article entitled, "How Many Administrators
are Enough?" which appeared in Unix Review, April 1991, and is available
on the web at <http://www.solutions.com/verber/how-many-admins.html>
Thanks to Mark for making this available.
However, I still caution that Your Mileage May Vary - no formulistic
approach can hope to catch all cases.
Subject: 9. I have a job opening for a Unix Sysadmin
comp.unix.admin is a technical group, with people looking for answers to
technical questions.
Job postings belong in misc.jobs.offered (or other appropriate *.jobs.*
groups), not comp.unix.admin.
SAGE has two related items: a sage-jobs-offered mailing list
(subscription is for SAGE members only, but others can post jobs
to the list - send mail to majordomo@usenix.org containing the
line
info sage-jobs-offered
for guidelines) and a SAGE Jobs Wanted page
(<http://www.sage.usenix.org/sage/jobs/jobs-wanted.html>)
where SAGE members looking for work can announce their availability.
Subject: 10. What professional/user groups exist for sysadmins?
USENIX <http://www.usenix.org/> has a sub-group, SAGE
<http://www.sage.usenix.org/sage/>, the System Administrators Guild.
USENIX and SAGE sponsor several annual conferences, including the USENIX
Systems Administration Conference, LISA.
See the USENIX events page for more info <http://www.usenix.org/events/>
SAGE also has some affiliated regional groups:
<http://www.sage.usenix.org/sage/locals/sage-localgroups.html>
In addition, you may want to ask your vendor if they can recommend any
local user groups.
Subject: 11. How do I remove a file that starts with a "-"?
The short answer is "rm ./-name". The long answer is this question is
answered in the comp.unix.questions FAQ. See section 2.1 of the
comp.unix.questions FAQ.
<ftp://rtfm.mit.edu/pub/usenet/news.answers/unix-faq/faq/>.
Subject: 12. How do I undelete a file in Unix?
In general, you don't - you restore from backups. For a more in-depth
discussion, see section 3.6 of the comp.unix.questions FAQ
<ftp://rtfm.mit.edu/pub/usenet/news.answers/unix-faq/faq/>.
Subject: 13. Where can I find automated pager software?
There is sendpage, tpage, HylaFax, QuickPage, and others. See the IXO
mailing list FAQ <ftp://ftp.airnote.net/pub/paging-info/ixo.faq> for details.
[WARNING - the above URL seems no longer be valid.]
HylaFax is available from <http://www.vix.com/hylafax/>
QuickPage is at <http://www.qpage.org/>
Subject: 14. How do I disable a user account?
There are two main ways; one is to star out the password field (placing
a "*" in front of the password entry), and the other is to change the
shell to something like /usr/local/bin/expired or /bin/false. To be on
the safe side, some people do both.
In either case, some other things your should look out for:
any .rhosts file should be removed or renamed
any currently running jobs should be removed
any cron or at jobs owned by the user should be disabled
any program mail forwarding forwards to should be checked for backdoors
(e.g., open a shell on some high number port after receiving mail with
"XYZZY" in the subject.) or disabled.
other accounts on any hosts.equiv machines should be disabled
other access files (for example if you're using ssh).
To be on the safe side, you might consider making the home directory
inaccessible (chmod 000).
Subject: 15. What can I do to secure my system?
That's a large topic. Some tips:
Subscribe to newsgroups comp.security.announce, comp.security.unix, and
the bugtraq mailing list <listserv@netspace.org - "subscribe bugtraq">.
Subscribe to the .announce newsgroup of your OS (see section 22).
Subscribe to appropriate OS-specific security mailing lists.
Check out the CERT archives at <ftp://ftp.cert.org/>. Run cops on your
system, and read the output. Install tripwire if you're worried about
hackers or virii altering your files.
Enable password shadowing if your OS supports it. Install one of the
fascist password checkers to help prevent users from choosing poor
passwords.
Wieste Venema has written a whole host of good stuff, including
tcpwrappers, replacement daemons with improved logging, and with Dan
Farmer wrote Satan and "The Admin Guide to Cracking" (also know as
_Improving the Security of Your Site by Breaking Into it_). His archive
site is at <ftp://ftp.win.tue.nl/pub/security/>
See also the computer-security/security-patches FAQ, which is posted
monthly to this newsgroup, or available from <ftp://iss.net/pub/faq/>.
If you've already been broken into, or for more information on securing
your system, read the compromise FAQ, also posted monthly to this
newsgroup, or available from <ftp://iss.net/pub/faq/>.
Subject: 16. What are some useful sysadmin utilities I might want to install?
top (a system process monitor)
<ftp://eecs.nwu.edu/pub/top/>
lsof (LiSt Open Files)
<ftp://vic.cc.purdue.edu/pub/tools/unix/lsof/>
sudo (limited root access)
<http://www.courtesan.com/courtesan/products/sudo/>
Samba (a LanManager like fileserver - file and printer
access to your Unix host from Win95, Windows for Workgroups, and WinNT)
<http://samba.anu.edu.au/samba/>
swatch (System WATCHer, configurable perl syslog watcher)
<ftp://ftp.Stanford.EDU/general/security-tools/swatch/>
procmail (mail processor)
<ftp://ftp.informatik.rwth-aachen.de/pub/packages/procmail/>
netcat (network pipes from the command line)
<ftp://ftp.avian.org/src/hacks/nc110.tgz>
Expect (interactive program automation)
<http://expect.nist.gov/>
See also section 15.
Subject: 17. Where can I get menu software for novice users?
If you're familiar with Perl and looking to roll your own, a good place
to start is <ftp://isum.iastate.edu/pub/perl/perlmenu.v3.2.tar.Z>
[Other suggestions?]
Subject: 18. How can I mirror files via FTP/HTTP? / How can I automate FTP?
A common way to mirror FTP is to use "mirror", a perl script written
for this purpose. "mirror" can be found at
<ftp://sunsite.doc.ic.ac.uk/computing/archiving/mirror/>
<ftp://ftp.th-darmstadt.de/pub/networking/mirror/>
<ftp://ftp.sun.ac.za/pub/unix/packages/mirror/>
The GNU program, "wget", can do http mirroring as well ftp. It should be
available from your local GNU archive, or <ftp://prep.ai.mit.edu:/pub/gnu/>
ncftp ("nice" ftp) can also do mirroring and command-line driven ftp,
useful for automating ftp in scripts. <ftp://ftp.probe.net/pub/ncftp/>
Expect <http://expect.nist.gov/> is a general-purpose tool for automating
interactive applications, including ftp, and makes a good addition to
any System Administrator's toolbox.
For a more in depth discussion of automating ftp, Cameron Laird has
collected a page of notes at
<http://starbase.neosoft.com/~claird/comp.unix.programmer/ftp_automation.html>
Subject: 19. How do I set up multiple IP addresses on a single interface?
This is OS Specific. Check your OS's FAQs (section 22), or see the "1
Ethernet, Many IP's" web page: <http://www.your.net/multi-homed/>
[Update: this seems to have disappeared. Anyone know where it went, or
another good resource on this topic? Alternately, now that http
supports multiple domains with one IP, perhaps this Question should be
dropped, as it's no longer "Frequent". <mailto:khockenb@stevens-tech.edu>]
Subject: 20. I'm looking to set up a firewall
Then you probably want comp.security.firewalls.
Subject: 21. I'm thinking of starting an Internet Service Provider
Run, do not walk, to the INTERNET PROVIDER RESOURCES web pages
<http://www.amazing.com/internet/>. They have a great FAQ on running
an ISP, tips, tricks, and pointers to appropriate mailing lists.
Subject: 22. I have OS <xxx>, how do I ...?
If you suspect that what you are attempting to do is specific to the
version of UNIX you are using, you may want to ask your question in a
newsgroup specific for your OS; you may also want to check your vendor's
web site and your OS's FAQs. Finally, there tend to be ftp archives for
each OS, where you can find patches and ported software.
AIX
====================
Newsgroups: comp.unix.aix
Vendor: <http://www.ibm.com/>
FAQ(s): <ftp://rtfm.mit.edu/pub/usenet/news.answers/aix-faq/>
Major ftp sites: <ftp://aixpdslib.seas.ucla.edu/pub/>
Security mailing list: aixserver@austin.ibm.com, subject "subscribe
Security"
BSDI
====================
Newsgroups: comp.unix.bsd.bsdi.announce, comp.unix.bsd.bsdi.misc
Vendor: <http://www.bsdi.com/>
FAQ(s): <http://www.bsdi.com/support/misc/faq.mhtml>
Major ftp sites: <ftp://ftp.bsdi.com/>
Security mailing list: [?]
Data General UNIX (aka DG/UX)
========================
Mailing List: majordomo@interlinx.bc.ca, body "subscribe dg-users"
Digital UNIX (aka OSF/1)
========================
Newsgroups: comp.unix.osf.misc, comp.unix.osf.osf1
Vendor: <http://www.digital.com/>
FAQ(s): <ftp://ftp.digital.com/pub/Digital/dec-faq/Digital-UNIX>
Major ftp sites: <ftp://gatekeeper.dec.com/>, <ftp://ftp.digital.com/>
Security mailing list: [?]
FreeBSD
====================
Newsgroups: comp.unix.bsd.freebsd.announce, comp.unix.bsd.freebsd.misc
Vendor: <http://www.freebsd.org/>
FAQ(s): <http://www.freebsd.org/FAQ/FAQ.html>
Major ftp sites: <ftp://ftp.freebsd.org/>
Security mailing list: Majordomo@freebsd.org, body "subscribe freebsd-security"
notifications only: "subscribe freebsd-security-notifications"
HPUX
====================
Newsgroups: comp.sys.hp.hpux
Vendor: <http://www.hp.com/>
FAQ(s): <ftp://rtfm.mit.edu/pub/usenet/news.answers/hp/hpux-faq>
Support URL: <http://us-support.external.hp.com/>,
<http://europe-support.external.hp.com/>
Major ftp sites: <http://hpux.cs.utah.edu/>
Security mailing list: <http://us-support.external.hp.com>
(for US, Canada, Asia-Pacific, & Latin-America)
<http://europe-support.external.hp.com> (for Europe)
IRIX
====================
Newsgroups: comp.sys.sgi.admin, comp.sys.sgi.announce,
comp.sys.sgi.apps, comp.sys.sgi.audio, comp.sys.sgi.bugs,
comp.sys.sgi.graphics, comp.sys.sgi.hardware, comp.sys.sgi.misc
Vendor: <http://www.sgi.com/>
FAQ(s): <ftp://viz.tamu.edu/pub/sgi/>
Major ftp sites: <ftp://ftp.sgi.com/>, <ftp://sgigate.sgi.com/>,
<http://reality.sgi.com/employees/billh_hampton/anonftp/>
Security mailing list: wiretap-request@sgi.com, body
"subscribe wiretap Your-Email-Address"
"end"
Linux
====================
Newsgroups: comp.os.linux.advocacy, comp.os.linux.announce,
comp.os.linux.answers, comp.os.linux.development.apps,
comp.os.linux.development.system, comp.os.linux.hardware,
comp.os.linux.m68k, comp.os.linux.misc, comp.os.linux.networking,
comp.os.linux.setup, comp.os.linux.x
Vendor: <http://www.ssc.com/linux/>
FAQ(s): <http://sunsite.unc.edu/LDP/linux.html>
Major ftp sites: <ftp://sunsite.unc.edu/pub/Linux/>,
<ftp://tsx-11.mit.edu/pub/linux/>
Security mailing list: Majordomo@linux.nrao.edu, body "subscribe linux-alert"
NetBSD
====================
Newsgroups: comp.unix.bsd.netbsd.announce, comp.unix.bsd.netbsd.misc
Vendor: <http://www.netbsd.org/>
FAQ(s): <http://cynjut.neonramp.com/FAQ.html>
Major ftp sites: <ftp://ftp.netbsd.org/>
Security mailing list: majordomo@netbsd.org, body "subscribe tech-security"
NeXTStep
====================
Newsgroups: comp.sys.next.advocacy, comp.sys.next.announce,
comp.sys.next.bugs, comp.sys.next.hardware, comp.sys.next.marketplace,
comp.sys.next.misc, comp.sys.next.programmer, comp.sys.next.software,
comp.sys.next.sysadmin
Vendor: <http://www.next.com/>, <http://www.apple.com/>
FAQ(s):
Major ftp sites: <ftp://ftp.next.com/>
Security mailing list: [?]
OpenBSD
====================
Newsgroups: comp.unix.bsd.openbsd.announce, comp.unix.bsd.openbsd.misc
Vendor: <http://www.openbsd.org/>
FAQ(s): <http://www.openbsd.org/>
Major ftp sites: <ftp://ftp.openbsd.org/>
Security mailing list: tech or misc@openbsd.org to submit bug reports
SCO
========================
Newsgroups: comp.unix.sco.announce, comp.unix.sco.misc,
comp.unix.sco.programmer, comp.unix.xenix.sco
Vendor: <http://www.sco.com/>
FAQ(s):
Major ftp sites: A list can be retrieved from
<ftp://ftp.celestial.com/README.sco-sites>
Security mailing list: [?]
Solaris
========================
Newsgroups: comp.unix.solaris (see also the list under SunOS)
Vendor: <http://www.sun.com/>
FAQ(s): <ftp://ftp.fwi.uva.nl/pub/solaris/>
Major ftp sites:
Security mailing list: Send mail to "security-alert@sun.com" with
the subject line "SUBSCRIBE CWS your-mail-address"
SunOS
====================
Newsgroups: comp.sys.sun.admin, comp.sys.sun.announce,
comp.sys.sun.apps, comp.sys.sun.hardware, comp.sys.sun.misc,
comp.sys.sun.wanted
Vendor: <http://www.sun.com/>
FAQ(s): <ftp://ftp.ece.uc.edu/pub/sun-faq/FAQs/>
Major ftp sites:
Security mailing list: [?]
Ultrix
========================
Newsgroups: comp.unix.ultrix
Vendor: <http://www.digital.com/>
FAQ(s): <ftp://ftp.digital.com/pub/Digital/dec-faq/ultrix>
Major ftp sites: <ftp://gatekeeper.dec.com/>, <ftp://ftp.digital.com/>
Security mailing list: [?]
Subject: 23. Help! Root doesn't have a valid password entry/
We lost the root password!
The typical example of the first is a typo in root's shell entry. The
second can happen when employees leave, or you inherit a machine, or you
just plain forgot. In both cases, the usual answer is to reboot the
machine from the installation media, then mount / and edit the password
file. Check your system's manuals or OS FAQ for more information on how
to do this, and don't forget to brush up on your ed(1) skills. :-)
On some systems, you can fix this problem by booting into single user mode
(check your OS manuals for how to do that). However, many modern Unixes
now require the root password for single user mode, so the installation
media boot is the simplest "always works" solution.
Subject: 24. How do I determine what process owns a socket/
what files are open by which processes?
If your version of UNIX has fuser, check the man page. On several
UNIX systems, fuser can be used to do these things. If your OS doesn't
have fuser (or maybe even if you do), install lsof.
lsof stands for 'LiSt Open Files' and is available from
<ftp://vic.cc.purdue.edu/pub/tools/unix/lsof/>
and is a handy tool for any sysadmin.
Subject: 25. What alternatives are there to sendmail?
exim, qmail, smail, and zmailer are all free, source-available
replacements for sendmail, some more "drop-in" than others.
[If the maintainers of the above mailers would like to mail me a
one-paragraph blurb about their mailer, I would gladly include them
here. -Kurt]
exim: <http://www.exim.org/>
qmail: <http://www.qmail.org/>
smail: <ftp://ftp.uu.net/archive/networking/mail/smail/>
zmailer:<ftp://ftp.funet.fi/pub/unix/mail/zmailer/>
See also the "UNIX Email Software Survey FAQ" posted to comp.mail.misc
and news.admin.misc
<ftp://rtfm.mit.edu/pub/usenet-by-group/comp.mail.misc/>
Subject: 26. How can I print to/from Windows95/NT and my Unix box?
Install samba, available from <http://samba.anu.edu.au/samba/>
Samba will let you share Unix printers and disks with Windows 95 and
WinNT, and comes with a shell script "smbprint" to let you print to
95/NT from your Unix host.
Subject: 27. What free software can I use to set up mailing lists?
See the "Mailing list management software FAQ"
<ftp://ftp.uu.net/usenet/news.answers/mail/list-admin/software-faq>
Subject: 28. How can I kick off inactive users?
idled <http://www.darkwing.com/idled/>
To quote the web page:
Idled (pronounced idle-dee) is a program that will run in the
background on a machine and monitor the current tty sessions. It can
be configured to log out users that have been idle for too long or
logged on for too long. It can also prevent users from being logged in
too many times, and refuse users from being logged in at all.
Subject: 29. How can I change passwords from a script?
Expect <http://expect.nist.gov/> can do this, by scripting responses to
passwd, and the distribution comes with "autopasswd" to do this.
Also with expect is mkpasswd, which will generate passwords and optionally
run passwd.
Subject: 30. Disclaimer and Copyright information
Disclaimer
This article is provided as is without any express or implied
warranties. While every effort has been taken to ensure the
accuracy of the information contained in this article, the
author assumes no responsibility for errors or omissions, or for
damages resulting from the use of the information contained
herein.
Copyright
This FAQ is Copyright (C) 1998 by Kurt M. Hockenbury. The right
to reproduce this FAQ, in whole or in part, in electronic form
is granted on the condition that credit is given. CD-ROM
manufacturers are requested (but not required) to send the
author a copy. For publication in non-electronic form, contact
the author.
Corrections, suggestions, marriage proposals, and ridiculously lucrative
job offers welcome.
Kurt Hockenbury <khockenb@stevens-tech.edu>
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