Admin Commands

This document will cover the Unix Admin commands that are largely the same on all flavors of Unix. (Lot of clean up is needed. For now, just dumping commands from cmd.admin.ref that should not go to sol.html)

CMD


dmesg   : display error log messages, like /var/adm/message, etc 
          obsolete by syslogd


du -kxS *       = display space usage Summary for only (x) one file sys (ie local)
        -d      = solaris native du, do not cross fs boundary, good for du -dsk / and only report ufs, sans nfs.
                  BUT du -dsk * will cross ufs and nfs that are mounted at the root level, such as /nfshome :(
        -x      = gnu du, "only 1 fs", but only Linux has desired behaviour like solaris -d
du -dk  / | sort -n | less      # use in solaris
du -skx * | sort -n | less      # use in linux          ??

df -kl          = report fs space usage of local fs, solaris and linux


## port mapper, remote procedure call.  NFS, YP etc use this protocol.
rpcinfo -b ypserv 1 (and 2)     find out all nis server on the subnet
rpcinfo -p tin-linux                            : show all rpc progs on machine tin-linux
rpcinfo -n 2049 -u tin-linux 100003 : see if nfs server is running
rpcinfo -n  802 -u tin-linux 100005 : see mountd info
rpcinfo -n 1048 -u tin-linux 100005 : see mountd info
        # note that mountd port may differ, see output of rpcinfo -p


nice, renice, priocntl:         change scheduling priority of process
        (ps/top, higher priority has higher numberic value 0=lowest, 100?=highest
        nice, higher number = nicer = lower priority
        -ve value of nice means not-nice, ie get more sys res, settable by root)

        eg renice 10 -p [pid]   : renice the process to 10 (from usual 0), thus making it to have less priority and demand less sys resource

        priocntl -s -p -5 -i pid 8200 :
        set the priority of process #8200 to -5.
        -s = set
        -p = priority
        -i pid = specify class of process, can group by parent pid, etc.



date --set [datestring] : linux, set date/time of machine, the string can almost be anything.
catman -w -M /usr/local/man     : rebuild the man page index for the dir /usr/local/man
catman -w       : probably rebuild based on $MANPATH



dhclient        = get dhcp address from server for current client.
(linux only?  move...)


---
99.999% uptime allow for 5.26 min of downtime in 1 year.
99.99%  allow for  52 min of downtime.
99.95%  allow for 263 min of downtime, a bit less than  4.5 hours.
99.9%   allow for 526 min of downtime, a bit less than 10   hours.


chroot


#!/bin/sh

#The following shell script builds a chroot environment for OpenSSH 3.7.1p2 on a Solaris 7 Sparc system.
# source:
#http://www.brandonhutchinson.com/chroot_ssh.html
# instructions:
# 1. get openssh source w/ chroot from chrootssh.sourceforge.net
# 2. Create the chroot environment.
#Note: the file system containing the chroot jail must be mounted suid. Attempting to use a chroot jail in a nosuid-mounted file system may result in the following error message:
#ld.so.1: /bin/sh: fatal: /dev/zero: open failed: No such file or directory
#Killed
#Remounting the nosuid file system with mount -o remount,suid file_system will not fix the problem. You must unmount the file system, remove nosuid from /etc/vfstab (if applicable), and remount the file system.

#CHROOT_DIRECTORY=chroot_directory
CHROOT_DIRECTORY=/lhome/chroot

#mkdir $CHROOT_DIRECTORY
cd $CHROOT_DIRECTORY

# Create directories
mkdir -m 755 -p bin dev usr/local/ssl/lib usr/local/lib usr/local/libexec usr/lib usr/bin usr/platform/`uname -i`/lib

# Copy files
cp -p /bin/sh $CHROOT_DIRECTORY/bin/sh
cp -p /usr/bin/cp /usr/bin/ls /usr/bin/mkdir /usr/bin/mv /usr/bin/rm /usr/bin/rmdir $CHROOT_DIRECTORY/usr/bin
cp -p /usr/lib/ld.so.1 /usr/lib/libc.so.1 /usr/lib/libdl.so.1 /usr/lib/libgen.so.1 /usr/lib/libmp.so.2 /usr/lib/libnsl.so.1 /usr/lib/libsocket.so.1 /usr/lib/librt.so.1 /usr/lib/libaio.so.1 $CHROOT_DIRECTORY/usr/lib

cp -p /usr/local/lib/libz.so $CHROOT_DIRECTORY/usr/local/lib
cp -p /usr/local/libexec/sftp-server $CHROOT_DIRECTORY/usr/local/libexec
cp -p /usr/local/ssl/lib/libcrypto.so.0.9.6 $CHROOT_DIRECTORY/usr/local/ssl/lib
cp -p /usr/platform/`uname -i`/lib/libc_psr.so.1 $CHROOT_DIRECTORY/usr/platform/`uname -i`/lib

# Create required character devices
mknod $CHROOT_DIRECTORY/dev/zero c 13 12
mknod $CHROOT_DIRECTORY/dev/null c 13 2
chmod 666 $CHROOT_DIRECTORY/dev/zero $CHROOT_DIRECTORY/dev/null

# 3. Create the chroot user. The chroot user's home directory should use the following format:
# /path_to_chroot/./home_directory

# To support chrooted ssh and sftp, choose /bin/sh as the chroot user's shell.
# To support chrooted sftp-only, choose /usr/local/libexec/sftp-server as the chroot user's shell.
# ex. grep hutch /etc/passwd
# hutchib:x:1000:1:Brandon Hutchinson:/home/chroot/./home/hutch:/bin/sh
# When user "hutch" logs in via ssh or sftp, he will be chrooted to /home/chroot and placed in the /home/hutch directory.


##CHROOT_DIRECTORY=/lhome/chroot
# additional files needed for sftp
# files needed for ldd usr/local/libexec/sftp-server
cp -p /usr/lib/libresolv.so.2 $CHROOT_DIRECTORY/usr/lib
cp -p /usr/lib/libz.so 	 $CHROOT_DIRECTORY/usr/lib
cp -p /usr/lib/libmd5.so.1 	 $CHROOT_DIRECTORY/usr/lib
cp -p /usr/local/lib/libgcc_s.so.1  $CHROOT_DIRECTORY/usr/local//lib
# somehow not copied:
cp -p /usr/local/ssl/lib/libcrypto.so.0.9.7 $CHROOT_DIRECTORY/usr/local/ssl/lib

Config Files

/etc/passwd
/etc/groups
/etc/shadow
/etc/group

/etc/init.d/ (linux: /etc/rc.d/init.d/)

/etc/inet/inetd.conf
/etc/printcap  or /etc/printer.conf
/etc/motd
/etc/release            # see which os cd was used eg sol 8 01/00 for Jan 2000 build. 

/etc/resolv.conf        # dns setup
/etc/nsswitch.conf      # order of search for files/dns/nis
/etc/init.d/            # list of programs that are configured for possible start up/shutdown automatically.
                        # actual start in /etc/rc2.d and rc3.d


syslog

rsyslog config (Fedora doc)
/etc/rsyslogd.conf
$ModLoad imuxsock # provides support for local system logging (e.g. via logger command)

# default only listen to unix socket, this add udp
#module(load="imudp")
#input(type="imudp" port="514")

# default only listen to unix socket, this add tcp
module(load="imtcp")
input(type="imtcp" port="514")des support for local system logging


test with logger command. eg
logger -p authpriv.warn "test from w0000. tin.  tcpdump show trafficic on port 514 udp"
# -p priority in number   eg 
# -p facility.level       eg local3.info  def is user.notice

logger --udp # only use udp, port per /etc/services, typically 514
logger --tcp # -T to use TCP only
logger --port # -P to use port number other than that in /etc/services
logger --udp -n server -port 80486
rsyslogd.conf

#### if acting as syslog server accepting logs, need:

# Provides UDP syslog reception
$ModLoad imudp
$UDPServerRun 514
# Provides TCP syslog reception
$ModLoad imtcp
$InputTCPServerRun 514

$OmitLocalLogging off

$ActionFileDefaultTemplate RSYSLOG_SyslogProtocol23Format
# use ietf-syslog-protocol-23 : [pri]level 2021-02-09T13:19:43-08:00 prefix  

# trying this on beagle
*.*                                                   /var/log/syslog_all
*.info,mail.!none,authpriv.!none,cron.!none           /var/log/syslog


# Save news errors of level crit and higher in a special file.
uucp,news.crit                                          /var/log/spooler

faciliy.levels traps

# facilities

daemon.*  	# isc dhcpd send to this level by default, change eg 'log-facility local6;'
authpriv.*	# sudo stuff goes here, senstive stuff
auth.*          # replaces old facility "security"
kern.*          # user run of logger -p kern.anything will be converted to facility "user"
mail.*
cron.*
syslog.*
user.*          # user space 
local0.*
local7.*



# levels, decreasing severity
*.emerg
*.alert
*.crit
*.err
*.warning
*.notice
*.info
*.debug

*.none # ?? this is an exception rule, easier than using *.!warning , which doesn't exclude higher levels.


# in theory, the below should split out the ISC DHCPD log to its own file
# none were supposed to means exception for the specified facilities.
# after changing dhcpd.conf with log-facility local6;
# but ISC DHCPD is a PITA and insist in logging at daemon.info [PRI=30] :-\ )
*.info;mail.none;authpriv.none;cron.none;local6.none    /var/log/messages
local6.*                                                /var/log/dhcpd.log




# Log anything (except mail) of level info or higher.
# Don't log private authentication messages!
*.info;mail.none;authpriv.none;cron.none                /var/log/messages
#### that was advertised in https://www.rsyslog.com/discarding-unwanted-messages/
#### but i don't think it actually works...  ; was for template, ! would be needed for exclude... ???

## , separate multiple service to be logged ??
## ; template
## ! is for negate as per doc.  eg
## To select all cron syslog messages except those with the info or debug priority
cron.!info,!debug



rsyslogd that listen/accept syslog traffic from other hosts need these clause:

# Provides UDP syslog reception
$ModLoad imudp.so
$UDPServerRun 514

# Provides TCP syslog reception
$ModLoad imtcp.so
$InputTCPServerRun 514

NIS


ypcat (group, passwd)
ypstart         # linux
ypbind
ypinit          # client, specify machines to bind to
                # server, specify whether master or slave
ypwhich         # tell what NIS server machine is bound to.
passwd
yppasswd (obsolete, for combatibility only)

ypcat -k auto.master    (-k to display the key name too!)
ypcat -k auto.direct    (the direct map, use /-)

/var/yp/binding/DOMAIN/ypservers        # list of ypservers that can be used (non broadcast mode)



passwd 

pwconv  update shadow file based on new user additon to passwd (does not set password)
passwd  [uid]           change password for user
chown   [uid]:[gid]     /home/[user]    change user home dir ownership


shadow fields (all numbers are in days):
eg: username:cV5MnNBnaUIbM:13362:0:99999:7:::
    [---1--] [-----2-----] [-3-] 4 [-5-] 6 (78)
1: username 
2: encrypted password 
3: last password change - days since 1970/01/01.  Substract this number by:
 	12775 = days since 2005/01/01
	13140 = days since 2006/01/01
	13505 = days since 2007/01/01 
4: password next change  	   - 0 means password can change at any time.
5: password req change in X days   - 99999 means next life time :)
6: warning for expiration
7: account disactivation in X days - usually empty
8: acc expiration  		   - usually empty
9: reserved


w change : allowed next change : 


---

NIS+

nismatch  -M name=tin passwd.org_dir
nismatch  tinh        passwd 
nismatch  grpname     netgroup.org_dir

nisgrep ...

NIS server setup


vi map files
make

(eg /var/ypmaps, /var/yp).

NIS client
/etc/defaultdomain
/etc/hosts		list of all nis servers

ypinit -c 
setup NIS client.
Use a predefined list nis servers,  thus avoid the need to use broadcast.


NOTE: a user can belongs to a max of 16 groups, surplus will not be recongnized by the system
and suffer non group membership error.  
Client OS specific, defined in limits.h ::
limits.h:#define        NGROUPS_MAX     16      /* max number of groups for a user */

---

master server

domainname NISdomainName
ypinit -m			# /usr/lib64/yp/
ypserv


removing old slaves, p69:
ypcat -k ypservers | grep -v oldsvr | makedbm - /var/yp/`domainname`/ypservers

Hon's approach (-u = undo)
/usr/lib/yp/makedbm -u ypservers /tmp/ypservers
vi /tmp/ypservers			# update file, need all slave and master
makdebm /tmp/ypservers ypservers	# recreate the ypservers map
makdebm ypservers /tmp/ypservers	# not sure of param seq
# at the end, ypcat -k ypservers need to list the master server as well.


in practice, I did:

cat /var/ypmaps/yp_slave.txt | makedbm - ypservers
or
cd /var/yp/arbor..com
cat yp_slave.txt | makedbm - ypservers

ypstop; ypstart # maybe needed, kill all yp* process, expecially yppush

and that will recreate ypservers.pag and timestamp ypservers.dir
yp_slave.txt is a text file that I create myself.  List all the slave servers, 
hostname should be okay if they are in /etc/hosts, but sometime used IP.

update the db w/o pushing the maps to the clients, which maybe down:
./make NOPUSH=true passwd


2004/01 getting issues about after update NIS master passwd, make and stuff
client don't see the latest changes, even if they appear on ypcat.
Seems to be client side resolver, editing nsswitch remove/readd nis seems to reset things.
Not sure if cuz NIS master need to timestamp other things.


1996/11/03 geneusa

ypservers.txt need to have key and actual entry, so file needed to be:
(and no # comments, # is not treated specially)

verso           verso.geneusa.com
papp-bapp1 papp-bapp1.geneusa.com
pdir-nis01 pdir-nis01.geneusa.com

and watch out for tailing space at the end of the line, which will be incorporated into the server name!
and result in host not found!!

cat ypservers.txt | /usr/lib/yp/makedbm - ypservers

the final dbdump file named ypservers need to be in the folder of the domain name, eg
/var/yp/tularik.com/ypservers



Hmm... very strange... more testing using make reveals that the makdebm for ypservers is not needed!

all that make wants is that there is a plain text file in /var/yp/ypservers
one host per line, no other format.  make depend on this to do push.

eg:
# cat ypservers   # the orig file
verso.geneusa.com
firth.geneusa.com




---

setting up slave server  (on linux)

Linux:
http://www.linux.org/docs/ldp/howto/NIS-HOWTO/ypserv.html

get ypserv rpm
domainname ...
ypinit -s MASTER-hostname	(/usr/lib64/yp)
ypserv				(/etc/init.d/ypserv)

don't forget to update appropriate files:
/etc/nsswitch.conf
/etc/sysconfig/network 
/etc/yp.conf		can have localhost, and ypwhich will return current machine
need to be setup correctly to be in NIS DOMAIN to begin with.


rpcinfo -u localhost ypserv	# test it

update slave's crontab to grp info using ypxfr





---


Adding new maps.

On master server, edit 
auto_master
plus any additional files, such as auto_products
Then, need to update Makefile to create dbm file out of the source.
Remember the pickiness of Makefile req Tab as separator in many places!

Then, after the Makefile is updated, the slave servers need to be updated also.

On the NIS slave, redo ypinit -s 
so that it will reread what maps are available and load them all.
Otherwise, they will never get the new maps!!



----


NIS client setup for RH9 in brio.  (2003/07)

vi /etc/sysconfig/network :
HOSTNAME=
NISDOMAIN=brio.com
DOMAINNAME=brio.com

vi /etc/nsswitch.conf, edit lines to match the following:
passwd:     files nis
shadow:     files nis
group:      files nis
automount:  files nis

# create startup scripts
cd /etc/rc.d/rc3.d
ln -s ../init.d/ypbind ./S27ypbind
cd /etc/rc.d/rc5.d
ln -s ../init.d/ypbind ./S27ypbind

start NIS client:
/etc/init.d/ypbind start

start automounter:
/etc/init.d/autofs start

restart ssh daemon (if you forget to do this, NIS user will NOT be able to loing!):
/etc/init.d/sshd restart




NTP



Solaris


"central ntp server", ie, main machine that sync to outside time server 
of (startus 1 or 2), and in turn act like main time server for local office.
At TiLeg, this was blazer, 10.215.20.8

cp /etc/inet/ntp.server /etc/inet/ntp.conf

change:

server 204.87.183.6 prefer
fudge  204.87.183.6 1 stratum 4
broadcast 10.215.20.255 ttl 4           # port 123
# 204.87.183.6 is reloj.kjsl.com in Salinas, CA, USA.
# there are other public clock server.



Then, on each subnete, wants to have a broadcast server that send out
NTP info, so any clients on that network can listen to it and sync its clock.


server 10.215.20.8 prefer		# blazer, which is "master NTP server"
broadcast 10.215.11.255 ttl 4           # port 123

Solaris client config


On each client, setup to listen to NTP.

cp /etc/inet/ntp.client /etc/inet/ntp.conf

Really just need one line in it, indicating it listen to broadcast NTP packets:

broadcastclient

Alternatively, it can listen to a specific server via:
server 10.215.20.8 prefer


Linux, as client

cp -pa /etc/rc3.d/K74ntpd /etc/rc3.d/S74ntpd
cp -pa /etc/rc5.d/K74ntpd /etc/rc5.d/S74ntpd
/etc/rc3.d/S74ntpd start

There is already a file /etc/ntp.conf with lot of comments, need to update it
as:

A simple client config that listen to broadcast clock:
/etc/ntp.conf ::
	broadcastclient

A client that listen to specific server:
	server cookoo.uxville.com
	server ticktick.uxville.com

A more involved linux config (details TBA):
	server  127.127.1.0     # local clock
	fudge   127.127.1.0 stratum 10
	server  cookoo.uxville.com

	driftfile /var/lib/ntp/drift
	broadcastdelay  0.008
	authenticate yes
	keys            /etc/ntp/keys		# need to actually setup own key



AIX


AIX, as client that listen to broadcast clock:

/etc/ntp.conf ::
	broadcastclient
	driftfile /etc/ntp.drift
	tracefile /etc/ntp.trace

startsrc -s xntpd

init script to uncomment /etc/rc.tcpip



HPUX


/etc/ntp.conf
	broadcastclient
	driftfile /var/ntp/ntp.drift
	statsdir  /var/ntp/ntpstats


/etc/rc.config.d/netdaemon, change:
	export NTPDATE_SERVER=10.215.22.5       #bigsur
	export XNTPD=1				# def=0, so it won't start
	export XNTPD_ARGS=


/sbin/rc2.d/S660xntpd start

NTP-like for windows



An article covering time sync optioins for windows:

http://geodsoft.com/howto/timesync/wininstall.htm

Precompiled SNTP client for windows NT system, refered from above.

http://sourceforge.net/projects/nettime/

Install it as adminstrator, say yes to setup as service.
Do configuration, use 10.215.20.8 (blazer) as server.
It request for 5 machines, but right now we don't have that many NTP server.
Could use the server in the various vlan, which really sync to blazer.


SNMP (Solaris)


/usr/local/ucd-snmp  aka net snmp, sunfreeware pkg.

snmpwalk  rlau-sun public 
snmpget   rlau-sun public iso.3.6.1.2.1.1.6.0

# rocky 8 get from
yum install net-snmp-utils

/etc/rc3.d/S76snmpdx

/etc/snmp/conf

snmpd.conf
snmpdx.acl	

but could not change which manchine allowed to query it.
acl list doesn't seems to work.
manager list in snmpd.conf doesn't seem to respond either.

solaris also have a mibiisa "sub-agent" which listen to non std snmp port (161).
It seems to be random port and talk to master agent snmpdx.

essentially, no way to change which ip it binds to (eg in firewall).
no way to restrict which client the agent will respond to.
Lacking man pages, and thing is probably buggy.


solaris package:

SUNWmibii       Solstice Enterprise Agents 1.0.3 SNMP daemon
SUNWsacom       Solstice Enterprise Agents 1.0.3 files for root file system
SUNWsasnm       Solstice Enterprise Agents 1.0.3 Simple Network Management Protocol
SUNWmipr        Mobile-IP (Root)	# mip, not mib
SUNWmipu        Mobile-IP (Usr)

---

stopping snmp in solaris

stopping 

/etc/rc3.d/S76snmpdx stop
/etc/rc3.d/S77dmi stop
cd rc3.d
mv S76snmpdx            _s76snmpdx
mv S77dmi               _s77dmi


Net-SNMP

Linux

RPM for tools: net-snmp-utils-...

Sample query commands: 

snmpget -v1 -c snmp4CSI machinename sysDescr.0
snmpget -v1 -c snmp4CSI machinename sysContact.0
snmpget -v1 -c snmp4CSI machinename sysLocation.0

RPM for snmp client config: net-snmp-5.1.2-11.EL4.7 + libraries (32 and 64 bit versions)


(snmpwalk command from From ZenOss package??)

snmpwalk -v1  -d -cpublic mybox.myco.net system
snmpwalk -v2c -d -cpublic mybox.myco.net system
	# -v1 or -v2c, use specific version that is supported by the client machine
	# -d = debug dump
	# -cCommunityName 
	# system keyword to limit what is walked, omit will return lot more info

snmpcmd	# cmd wrapped by snmpwalk, read man page for options.

##/etc/snmp/snmpd.conf 

# -----------------------------------------------------------------------------
com2sec local localhost snmp4ESI
## servers in the following area will not be allowed to do query with this client.
com2sec privnet 172.27.0.0/16 snmp4CSI
com2sec privnet 10.0.0.0/8 snmp4CSI
 
group rogroup v1 local
group rogroup v2c local
group rogroup usm local
group rogroup v1 privnet
group rogroup v2c privnet
group rogroup usm privnet
 
view all included .1
 
access rogroup "" any noauth exact all none none
 
# -----------------------------------------------------------------------------
# System Information
syslocation -use snmpd.local.conf instead-
syscontact  -use snmpd.local.conf instead-
 
# -----------------------------------------------------------------------------
# System Monitors
storageUseNFS 1
ignoredisk /proc
ignoredisk /etc/mnttab
ignoredisk /tmp
proc /usr/lib/ssh/sshd 10 1
proc /usr/sbin/cron 1 1
proc /usr/lib/inet/xntpd 1 1
disk / 10%
agentSecName internal
rouser internal
defaultMonitors yes
 
# -----------------------------------------------------------------------------
# Traps -- use the two closest ones to the region where the system will be installed.
informsink 172.27.166.43 
informsink 172.27.166.87
authtrapenable 1
  
# -----------------------------------------------------------------------------
# Extensions
master agentx


##/etc/snmp/snmpd.local/conf

syslocation USCA-SF
syscontact  US-Unix-Admin

Snooping for traffic:
tcpdump -vv -s0 -i eth0 host 172.140.92.112 and port 161

NetApp

NetApp's build in SNMP works with NetSNMP.
snmp				# display SNMP config
options snmp.access		# display which remote host can make SNMP queries

# sample config
snmp community delete               all
snmp community add                  ro   my-snmp-RO-cummunity
snmp traphost add                   172.27.166.43 
snmp traphost add                   172.27.180.87
snmp authtrap                       1
snmp init                           1
 
options snmp.access                 host=172.27.166.43,172.27.180.87,netapp-dfm,admin-host
options snmp.enable                 on

Solaris

For Solaris, don't use the stock snmp, but get Net-SNMP Agent package and the same linux config file above will work, placing it in /etc/snmp/conf/snmpd.conf. http://www.net-snmp.org

Concord nhSnmpTool MibWalk

CA provides this tool for Solaris (and windows?).  
Can query a machine and retrieve all the MIB thru automatic MIB-WALK.

It is just a tar file, no install required.

./nhSnmpTool -c snmp4CSI 10.222.2.19

And it will write output to dir/file under the tmp dir of where the tool is installed.
The output would consist of a very large number of OID numbers,
they are incomprehensible without more tools, 
but at least one can tell that the SNMP config is working.

SUDO


sudo cmd			# run a specific command as root

sudo -u svc-acct -H  bash	# become a specific user (-u), setting home dir (-H)
				# and run the specific shell as command



# simple sudoers file to allow specific users to become root.
# minimal fuss :)

User_Alias SUPERUSERS = sa admin toor
SUPERUSERS      ALL=(ALL) ALL

# User privilege specification
root    	ALL=(ALL) ALL
tinh            ALL=(ALL) ALL		# could have placed this user in alias section also
# user		hostlist=(userlist) commandlist


# below are not needed as ultimately ALL commands are allowed.
# but if future changes, then they can be enabled.  tested to work.
#GRETA_DOCKER   GRETADEV = NOPASSWD: /bin/sudo su - gitlab
#GRETA_DOCKER   GRETADEV = NOPASSWD: /bin/sudo su - runner
#GRETA_DOCKER   GRETADEV = (gitlab) NOPASSWD: ALL
#GRETA_DOCKER   GRETADEV = (runner) NOPASSWD: ALL
GRETA_DOCKER    GRETADEV = NOPASSWD: ALL




# sudoers eg (2)
# simple file that enable apache/oracle to start as root

sys_hudson ALL=(ALL) NOPASSWD: /etc/init.d/tomcat

# User alias specification
User_Alias      APACHE = applmgr

# Cmnd alias specification
Cmnd_Alias      HTTP_CMD = /u01/applmgr/ORADEVcomn/admin/scripts/ORADEV_oadevapp1/adapcctl.sh, \
                           /u01/applmgr/ORADEVora/iAS/Apache/Apache/bin/apachectl,  \
                           /u01/applmgr/ORADEVora/iAS/Apache/Apache/bin/httpd
Cmnd_Alias      TEST_CMD = /usr/bin/cat, /usr/bin/echo


APACHE  ALL = NOPASSWD: HTTP_CMD, TEST_CMD


# eg 2b:

Cmnd_Alias SU_MDL = /bin/su - mdl, /bin/su mdl
User_Alias MDL=thom,jay
Cmnd_Alias CHOWN_MDL = /bin/chown mdl\:mdl /usr/mdl/*
MDL ALL=(mdl) ALL, (root) SU_MDL, NOPASSWD: CHOWN_MDL


# eg 2c:

Cmnd_Alias SU = /usr/sbin/visudo, /bin/su
Cmnd_Alias SHELL = /bin/bash, /bin/csh, /bin/ksh, /bin/sh, /bin/tcsh, /bin/zsh
Cmnd_Alias FILE_READ = /bin/ls, /usr/bin/tail, /bin/cat, /bin/grep
Cmnd_Alias APP_SVR = /etc/init.d/httpd, /etc/init.d/tomcat, /etc/init.d/jboss
User_Alias ADMIN = username1, username2"

ADMIN ALL=(ALL) ALL, !SU, !SHELL,  NOPASSWD: FILE_READ, APP_SVR
# there is no need to prefix "NOPASSWD:" in front of APP_SVR commands, the clause will be applied to EOL.



# longer sudoers eg, (probably for the older version of sudo)
# http://www.courtesan.com/sudo/man/sudoers.html#examples
#

# User alias specification

User_Alias     REAL_ADMIN = tho, joycec, hhuynh
User_Alias     PSEUDO_ADMIN = jmedlin, terry
User_Alias     HELPDESK = wtang, sa
User_Alias     WEBMASTERS = lonly

Runas_Alias    OP = root, operatora
Runas_Alias    DB = oracle, sybase

# Host alias specification

Host_Alias     SPARC = its01, ges-sun2, trout :\
                HPUX  = cod, riptide :\
                AIX   = brine, chicklet :\
                LINUX = toolbox, ldap09 :\
                SGI = grolsch, dandelion, black :\
                ALPHA = widget, thalamus, foobar :\
                HPPA = boa, nag, python
Host_Alias     VLAN28 = 172.27.28.0/255.255.255.0
Host_Alias     CSNETS = 128.138.243.0, 128.138.204.0/24, 128.138.242.0
Host_Alias     SERVERS = master, mail, www, ns
Host_Alias     CDROM = orion, perseus, hercules

# Cmnd alias specification

Cmnd_Alias     DUMPS = /usr/bin/mt, /usr/sbin/dump, /usr/sbin/rdump,\
                        /usr/sbin/restore, /usr/sbin/rrestore
Cmnd_Alias     KILL = /usr/bin/kill
Cmnd_Alias     PRINTING = /usr/sbin/lpc, /usr/bin/lprm
Cmnd_Alias     SHUTDOWN = /usr/sbin/shutdown
Cmnd_Alias     HALT = /usr/sbin/halt
Cmnd_Alias     REBOOT = /usr/sbin/reboot
Cmnd_Alias     SHELLS = /usr/bin/sh, /usr/bin/csh, /usr/bin/ksh, \
                         /usr/local/bin/tcsh, /usr/bin/rsh, \
                         /usr/local/bin/zsh
Cmnd_Alias     SU = /usr/bin/su
Cmnd_Alias     TEST = /bin/cat

# User privilege specification

# %group indicate /etc/group

root           ALL = (ALL) ALL
%briosa        ALL = (ALL) ALL
%puser         localhost=/sbin/shutdown -h now

# CAPS are group defined here in sudoers file
REAL_ADMIN     ALL = NOPASSWD: ALL
PSEUDO_ADMIN   ALL = ALL
HELPDESK       ALL = KILL, DUMPS, /bin/ls, /bin/cat

babuv          VLAN28 = ALL

#operatora      ALL = DUMPS, KILL, SHUTDOWN, HALT, REBOOT, PRINTING,\
#               sudoedit /etc/printcap, /usr/oper/bin/

joe            ALL = /usr/bin/su operatora
bob            SPARC = (OP) ALL : SGI = (OP) ALL


# +netgroup membership (host or username)
jim            +biglab = ALL
+secretaries   ALL = PRINTING, /usr/bin/adduser, /usr/bin/rmuser

WEBMASTERS     www = (www) ALL, (root) /usr/bin/su www


ALL            CDROM = NOPASSWD: /sbin/umount /CDROM,\
               /sbin/mount -o nosuid\,nodev /dev/cd0a /CDROM, \
               /sbin/mount  /cdrom, \
               /sbin/umount /cdrom, \
               /sbin/mount  /mnt/cdrom, \
               /sbin/umount /mnt/cdrom 

# end

# user	       	hostlist=(userlist) commandlist
MDL 		ALL=(mdl) ALL, (root) SU_MDL, NOPASSWD: CHOWN_MDL
tin 		ALL=(all) /etc/init.d/httpd, /etc/init.d/jboss, NOPASSWD: /bin/cat, /bin/tail
Cmnd_Alias NETWORKING = /sbin/route, /sbin/ifconfig, /bin/ping, /sbin/dhclient, /usr/bin/net, /sbin/iptables, /usr/bin/rfcomm, /usr/bin/wvdial, /sbin/iwconfig, /sbin/mii-tool
Cmnd_Alias SVC_APP_SVR = /sbin/service sonatype_nexus
Cmnd_Alias FILE_READ = /bin/ls, /usr/bin/tail, /bin/cat, /bin/grep
User_Alias ADMIN = root, sa1, sa2
Cmnd_Alias WINESXAPRIVS = /sbin/shutdown, /sbin/init, /sbin/reboot
Cmnd_Alias WINAPRIVS = /sbin/shutdown, /sbin/init, /sbin/reboot
Cmnd_Alias LINUXAPRIVS = /usr/sbin/vgdisplay, /sbin/vgdisplay, /sbin/lvdisplay, /usr/sbin/lvdisplay, /sbin/pvdisplay, /usr/sbin/pvdisplay, /sbin/lspci, /usr/sbin/dmidecode, /usr/sbin/lsof, /usr/bin/md5sum, /usr/bin/shasum, /usr/bin/head, /sbin/fdisk -l, /sbin/service * status, /sbin/ethtool, /sbin/service nscd *, /usr/sbin/adreload, /usr/sbin/adflush, /usr/bin/tail, /bin/cat, /sbin/chkconfig --list
User_Alias ORA_DB_ADMINS = dba1,dba2
ORA_DB_ADMINS ALL=(ALL)NOPASSWD:/bin/su - oracle
Defaults env_keep = "COLORS DISPLAY HOSTNAME HISTSIZE INPUTRC KDEDIR LS_COLORS MAIL PS1 PS2 QTDIR USERNAME LANG LC_ADDRESS LC_CTYPE LC_COLLATE LC_IDENTIFICATION LC_MEASUREMENT LC_MESSAGES LC_MONETARY LC_NAME LC_NUMERIC LC_PAPER LC_TELEPHONE LC_TIME LC_ALL LANGUAGE LINGUAS _XKB_CHARSET XAUTHORITY"
User_Alias OPERATOR = rajshau1,willijos,galmifr1
User_Alias ORACLE=bielida1,gournaj1,hongli5,karnaha1,stockrai,maddeto1,karnaha1,oracle,shahsha
Cmnd_Alias SU = /usr/sbin/visudo, /bin/su
Cmnd_Alias FILE_WRITE = /bin/chown, /bin/chmod, /bin/chgrp, /usr/bin/emacs, /usr/bin/co, /usr/bin/ci, /usr/bin/rcsdiff, /usr/bin/rcs2log, /usr/sbin/cfagent, /bin/tar, /usr/bin/vi, /usr/bin/vim
User_Alias NAGIOSUSERS = nagios, nrpe
Cmnd_Alias NAGIOSCMDS = /usr/local/nagios/libexec/check_logfiles *, /usr/lib/nagios/plugins/check_logfiles *
Cmnd_Alias SU_MDL = /bin/su - mdl, /bin/su mdl
User_Alias MDL=thomproa,kondrja1,cheminfor
Cmnd_Alias APP_SVR = /etc/init.d/httpd, /etc/init.d/tomcat, /etc/init.d/jboss
Cmnd_Alias SOFTWARE = /bin/rpm, /usr/bin/up2date, /usr/bin/yum
Cmnd_Alias SERVICES = /sbin/service, /sbin/chkconfig
Cmnd_Alias LOCATE = /usr/bin/updatedb
Cmnd_Alias STORAGE = /sbin/fdisk, /sbin/sfdisk, /sbin/parted, /sbin/partprobe, /bin/mount, /bin/umount
Cmnd_Alias DELEGATING = /usr/sbin/visudo, /bin/chown, /bin/chmod, /bin/chgrp
Cmnd_Alias PROCESSES = /bin/nice, /bin/kill, /usr/bin/kill, /usr/bin/killall
Cmnd_Alias DRIVERS = /sbin/modprobe
Cmnd_Alias CHOWN_MDL = /bin/chown mdl\:mdl /usr/mdl/*
Cmnd_Alias SHELL = /bin/bash, /bin/csh, /bin/ksh, /bin/sh, /bin/tcsh, /bin/zsh
Defaults    always_set_home


# user	       	hostlist=(userlist) commandlist
root  ALL=(ALL) ALL
NAGIOSUSERS ALL = (root) NOPASSWD: NAGIOSCMDS
ORACLE ALL=(ALL) ALL
MDL ALL=(mdl) ALL, (root) SU_MDL, NOPASSWD: CHOWN_MDL
OPERATOR ALL=(ALL) NOPASSWD: FILE_READ
ADMIN  ALL=(ALL)  ALL, NOPASSWD: FILE_READ, NOPASSWD: /usr/prog/cfengine/2.2.10/sbin/cfagent, FILE_WRITE
%admins_nis_grp   ALL=(ALL) ALL,NOPASSWD:LINUXAPRIVS


DNS


nslookup
server ns1.att.net
set query=a
www.yahoo.com
set query=ns
set q=mx
set t=soa
yahoo.com
set q=any


set d2                  # place in debug level 2 , lot more info about record eg TTL
                        # diff output depending on implementation (eg, linux vs dos)

eg:

nslookup
> set query=soa
> ask-margo.com
Non-authoritative answer:
Server:  e3k-toadsman
Address:  192.168.188.1

ask-margo.com
        primary name server = ns1.dunlin.arvixe.com
        responsible mail addr = servers.arvixe.com
        serial  = 2016092722
        refresh = 86400 (1 day)
        retry   = 7200 (2 hours)
        expire  = 3600000 (41 days 16 hours)
        default TTL = 86400 (1 day)

> set q=ns
> ask-margo.com
Non-authoritative answer:
Server:  e3k-toadsman
Address:  192.168.188.1

ask-margo.com   nameserver = ns1.dunlin.arvixe.com
ask-margo.com   nameserver = ns2.dunlin.arvixe.com




---

dig

Usage:  dig [@global-server] [domain] [q-type] [q-class] {q-opt}
        {global-d-opt} host [@local-server] {local-d-opt}
        [ host [@local-server] {local-d-opt} [...]]




dig www.yahoo.com
dig soa fiu.edu.
dig mx  cs.fiu.edu.

dig -x 131.94.125.125
dig cs.fiu.edu @zorba.cs.fiu.edu any

generating hint file, use one of:

dig @f.root-servers.net . ns > root.cache
dig . ns > root.cache


first line seemed better in getting more complete list of servers.






TBD

old *.ref file content in here.








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