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Table of Contents

Chapter 1: Essential System Administration Pocket Reference

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This book serves as a quick reference to the most important system administration commands, options, configuration files, and tasks on Unix systems, including specifics for AIX, FreeBSD, HP-UX, Linux, and Solaris. For more details about any item or topic, consult a general system administration reference (e.g., Essential System Administration, Third Edition, O'Reilly & Associates).

Items in this book are grouped by topic (see the Table of Contents). Within each topic, items are in more-or-less alphabetical order, although related items are kept together (use the Index to find any particular item).

This book uses the following font and symbol conventions:

Italic

Used for the names of users and groups, files and directories, and replaceable parameters within normal text.

constant width bold

Used for Unix commands, options, program names, and configuration-file literals and keywords.

constant width italic

Used for replaceable parameters in commands, options, and configuration-file formats.

a|b

Indicates a choice among items (e.g., a or b).

[optional]

Optional items are enclosed in square brackets.

command+

Open source commands are marked by a plus sign.

su

su [-] [user] [-c "command"]

Run a command as another user (defaults to root). If no command is specified, a new shell is started. If the initial hyphen is included, then the user's login environment is duplicated.

Limiting access to su

AIX

Limited to groups listed in the sugroups attribute for root in /etc/security/user.

FreeBSD

Define the member list for group 0 as non-null.

Linux

Use the pam_wheelmodule in the su file.

su log file

AIX:

/var/adm/sulog

FreeBSD:

/var/log/messages

HP-UX:

/var/adm/sulog

Linux:

/var/log/messages

Solaris:

Specified in the SULOG setting in /etc/default/su.

Limiting direct root logins to the console

AIX

chuser ttys="/dev/lft,/dev/tty0" rlogin=false root

FreeBSD

Omit secure from all entries in /etc/ttys except console.

HP-UX

/etc/securettylists devices where

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Introduction and Font Conventions

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This book serves as a quick reference to the most important system administration commands, options, configuration files, and tasks on Unix systems, including specifics for AIX, FreeBSD, HP-UX, Linux, and Solaris. For more details about any item or topic, consult a general system administration reference (e.g., Essential System Administration, Third Edition, O'Reilly & Associates).

Items in this book are grouped by topic (see the Table of Contents). Within each topic, items are in more-or-less alphabetical order, although related items are kept together (use the Index to find any particular item).

This book uses the following font and symbol conventions:

Italic

Used for the names of users and groups, files and directories, and replaceable parameters within normal text.

constant width bold

Used for Unix commands, options, program names, and configuration-file literals and keywords.

constant width italic

Used for replaceable parameters in commands, options, and configuration-file formats.

a|b

Indicates a choice among items (e.g., a or b).

[optional]

Optional items are enclosed in square brackets.

command+

Open source commands are marked by a plus sign.

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The root Account

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su

su [-] [user] [-c "command"]

Run a command as another user (defaults to root). If no command is specified, a new shell is started. If the initial hyphen is included, then the user's login environment is duplicated.

Limiting access to su

AIX

Limited to groups listed in the sugroups attribute for root in /etc/security/user.

FreeBSD

Define the member list for group 0 as non-null.

Linux

Use the pam_wheelmodule in the su file.

su log file

AIX:

/var/adm/sulog

FreeBSD:

/var/log/messages

HP-UX:

/var/adm/sulog

Linux:

/var/log/messages

Solaris:

Specified in the SULOG setting in /etc/default/su.

Limiting direct root logins to the console

AIX

chuser ttys="/dev/lft,/dev/tty0" rlogin=false root

FreeBSD

Omit secure from all entries in /etc/ttys except console.

HP-UX

/etc/securettylists devices where root is allowed to log in (omit "/dev/" from the names).

Linux

Use the pam_securettymodule.

Solaris

/etc/default/login: CONSOLE=/dev/console

sudo+

sudo [options] command

Run the specified command using the sudo facility. After successfully entering his password, a user can use the sudo command without having to re-enter it for a grace period (defaults to 5 minutes).

Options

-v

Reset the grace period to its full length.

-K

Terminate the grace period.

-u user

Run the command as the specified user (rather than root).

-l

List allowed commands for the current user and host.

Configuration file: /etc/sudoers

# alias definitions
Host_Alias NAME=host[,host...] Named list of hosts
User_Alias NAME=user[,user...] Named list of users
Cmnd_Alias NAME=cmd[,cmd...]	Named list of commands

# user access entries
user host = cmds [: host = cmds...]

The final line grants access to the specified commands on the indicated host. User is the name of a user, a group (precede its name with %), or previously-defined user alias, and host and cmds are lists of individual hosts/commands and/or defined aliases. Precede an item with ! to deny access.

The sudo package provides the

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Essential Administrative Tools

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Vendor-provided system administration tools

The various operating systems provide the following GUI and menu-driven administrative tools.

AIX:

smit, wsm

HP-UX:

sam

FreeBSD:

sysinstall

Solaris:

admintool, smc

Linux:

redhat-config-* (Red Hat); yast2 (SuSE)

chroot

chroot directory command

Change the root to the specified directory, and then execute the specified command. The command will interpret all paths as starting from the specified directory (rather than /).

date

date MMDDhhmm[CC]YY[.ss]

Set the date and time (using a 24-hour clock). For example, the argument for 1:47 p.m. on September 5, 2002 is 0905134702.

file

file files

List the types of each specified file. Identification is made based on the "magic numbers" defined in the magic configuration file (its location varies by system).

find

find starting-dirs [matching-criteria-and-actions]

Locate files that have the specified characteristics, and perform the specified actions on each file. Starting-dirs is a list of one or more directories from which to start searching. If the matching-criteria expression returns a true value; then the specified actions are carried out on the matching file.

Matching-criteria options

-atime n

The file was last accessed exactly n days ago.

-mtime n

The file was last modified exactly n days ago.

-newer file

The file was modified more recently than file.

-size n

The file is n 512-byte blocks long (rounded up to next block).

-links n

The file's inode has exactly n hard links.

-type c

Specifies the file type: f (plain file), d (directory), l (symbolic link), p (named pipe), s (socket), b (block special file), c (character special file).

-fstype type

Specifies the filesystem type.

-name fname

The filename is fname.

-perm [-]p

The file's numeric access mode is p. If the hyphen is included, then only the bits set in p are compared to the file's access mode, and all other permissions are ignored.

-user username

The file's owner is username

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Devices and Device Files

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dmesg

dmesg Not available under AIX

Display boot and other system messages. Devices are listed within the messages as the devices are detected.

Vendor-specific device listing commands

AIX

lscfg                     List all devices.
lsdev -C -s scsi          List all SCSI devices.
lscfg -v -l device        Display device details.
lsattr -E -H -l device    Display device attributes.

FreeBSD

pciconf -l -v          List PCI devices.
camcontrol devlist      List SCSI devices.
usbdevs                 List USB devices.

HP-UX

ioscan -f -n            Display detailed device listing.
ioscan -f -n -C disk    Limit to device class.

Linux

lsdev          List major devices.
scsiinfo -l    List SCSI devices.
lspci          List PCI devices.
lsusb          List USB devices.

Solaris

getdev               List devices.
getdev type=class    Limit to device class.
devattr -v device    Display device detail.

In all cases, the optional r in special filenames refers to the character device (i.e., raw access mode), and the other name refers to the block device.

Disk partition special filenames

AIX

/dev/hdiskn (refers to entire disk)

n is the disk number. Example: /dev/hdisk1

FreeBSD

/dev/[r]ppnsmx (often shortened to /dev/[r]ppnx)

pp is a device-specific prefix (e.g., ad or wd for IDE disks, da for SCSI), n is the disk number, m is the slice number (physical partition), and x is the partition letter. Example: /dev/da1s1a

HP-UX

/dev/[r]dsk/cktidn

k is the controller number, i is the SCSI ID, and n is the disk number. Example: /dev/dsk/c0t4d1

Linux

/dev/[sd|hd]ym

The sd/hd prefix refers to SCSI/IDE disks, respectively, y is the disk letter (where a refers to the first disk, etc.), and m is the physical partition number. Example: /dev/hda1

Solaris

/dev/[r]dsk/cktid0sm

k is the controller number, i is the SCSI ID, and m is the physical partition number. Example: /dev/dsk/c0t4d0s2

CD-ROM device special filenames

AIX:

/dev/cd0

HP-UX:

/dev/dsk/cktid0

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File Ownership and Protection

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chmod

chmod [-R] access-string[,access-string...] files

Change the file mode of the specified files as directed in the access-string. -R operates recursively on any directories in the file list.

Access-string can be a numeric file mode or one or more symbolic permission strings; symbolic permission strings have the general syntax:

[class]+|-|=[type]

where class is one or more access class code letters: u for user, g for group, o for other, a for all. a is the default (although on some systems, omitting the access class causes the specified permissions to be limited by the current umask).

The second item is an operator: + to add permissions, - to remove them, and = to set permissions to the specified value.

Type is one or more access type code letters: r (read), x (execute), w (write), or one of the special types listed in the following section.

Special access types

X

Set execute access only if it has already been set for some access class.

t (save text mode/sticky bit) [numeric 1000]

When used for other access on a directory, restricts user file deletions to his own files.

s (SetUID and SetGID) [numeric 4000 and 2000]

When used with user and group access, causes a program to execute in the user/group context of the files's owner(s), rather than the user who ran it. Both require the corresponding execute access to be on.

SetGID access on a directory causes new file group ownership to follow the directory's group owner rather than the primary group of the creating user.

l (file locking: Solaris, some Linux) [numeric 2000]

Set mandatory file locking on reads/writes. Assign via the group access class; requires that group execute access is off.

chownchgrp

chown [-R] new-owner[:new-group] files chgrp [-R] new-group files

Change the user/group ownership of the specified files. The -R option performs a recursive operation on directories in files.

umask

umask mask

Set the default permission mode mask (the corresponding default mode is the octal compliment of mask).

AIX ACLs

acledit

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System Messages and Log Files

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File locations

syslog daemon configuration file

Usual:

/etc/syslog.conf

General message log file

Usual:

/var/log/messages

HP-UX:

/var/adm/syslog/syslog.log

Solaris:

/var/adm/messages

syslog subsystem configuration

FreeBSD:

/etc/rc.conf: syslogd_enable and syslogd_flag.

Linux:

/etc/sysconfig/syslog (SuSE): SYSLOGD_PARAMS and KERNEL_LOGLEVEL.

/etc/syslog.conf file format

facility[,facility].level[;facilities.level] dest

Facility is a list of one or more defined syslog "facilities," which are sources of system messages. Multiple facilities are separated by commas.

Level is a defined message severity level; all messages at that level and higher will be selected.

Multiple facility-level pairs may be listed, separated by semicolons. An asterisk may be used for either item; the asterisk refers to all facilities or all severity levels, except mark.

The final item is the message destination; it can be a full pathname to a file, a user or list of users to whom a message should be sent (* refers to all logged-in users), or @hostname (forward it to the syslog daemon on that host). Note that specified files must already exist.

Facilities

kern

The kernel.

user

User processes.

mail

The mail subsystem.

lpr

The printing subsystem.

daemon

System server processes.

auth

The user authentication system (nonsensitive information).

authpriv

The user authentication system (security sensitive information). Some systems have only one of auth and authpriv.

mark

Internal syslog time stamp messages (generated every 20 minutes by default).

local*

Eight local message facilities (0-7). Some operating systems define one or more of them.

Some systems define additional subsystem-specific facilities, such as ftp, news, uucp, syslog, etc.

Severity levels

emerg

System panic.

alert

Serious errors that require immediate attention.

crit

Critical errors, such as hard device errors.

err

Other errors.

warning

Warnings.

notice

Noncritical messages.

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Startup and Shutdown

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Booting the system manually

AIX

Little intervention is allowed. Boot from an alternate device by using the AIX bootlist command to set the device order.

FreeBSD

Select a disk and/or partition from the menu. Strike a key when prompted; then use the boot command (add -s for single-user mode). To boot an alternate kernel, use commands like:

unload
load filename
boot

HP-UX (> prompt)

List devices with the search command. Use bo xx to boot the device labeled xx in the search output (e.g., CD-ROM).

HP-UX (ISL> prompt)

Use the hpux command. Add -is (for single-user mode) and/or a pathname to boot an alternate kernel.

Linux (lilo boot loader)

The Tab key lists the boot choices; enter one choice to boot (e.g., linux). Add single to boot to single-user mode.

Linux (grub boot loader)

Use the following commands to specify all boot parameters:

grub> root (hd0,0)            Partition to boot from
grub> kernel path ro root=/dev/xdyn			 Kernel /root devs
grub> initrd path			    If needed
grub> boot 	                Initiate the boot

When specifying the root device, x is either h or s, y is the disk letter, and n is the partition number.

Solaris

Enter L1-a or Stop-a to get the ok prompt. From there, the boot command starts a boot (-s selects single-user mode). The boot cdrom command boots from CD-ROM.

System V-style run levels

0

Halted state: conditions when it is safe to turn off the power.

1

System administration/maintenance state.

S and s

Single-user mode.

2

Multiuser mode (AIX default).

3

Remote file-sharing state (HP-UX and Solaris default).

4, 7, 8, 9

Administrator-definable system states. HP-UX and Solaris do not support run levels 7 through 9.

5

Same as run level 3 but running a graphical login program on the system console (Linux default).

6

Shutdown and reboot state.

Q and q

Pseudo-state that tells init to reread its configuration file.

a, b, c

Pseudo-run levels that can be defined locally. When invoked, they cause init to run the commands in /etc/inittab without changing the current (numeric) run level.

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User Accounts

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/etc/passwd

The password file

username:x:UID:GID:user-info:home-dir:login-shell

username

User account login name (generally limited to 8 characters).

x

Traditional password field, set to a fixed character (usually x) when a shadow password file is in use. AIX uses an exclamation point (!), and FreeBSD uses an asterisk (*).

UID

The user identification number.

GID

The user's primary group membership.

user-info

Conventionally, contains the user's full name and, possibly, other job-related information (e.g., office location or phone number). Up to five comma-separated subfields may be defined.

home-dir

The user's home directory.

login-shell

The program used as the command interpreter for this user. On most systems, the /etc/shells file lists the full pathnames of valid shell programs; on AIX systems, valid shells are listed in the shells field in the usw stanza of /etc/security/login.cfg:

shells = /bin/sh, /bin/csh, ...

Shadow password files

/etc/shadow (Linux and Solaris)

user:pwd:changed:minlife:maxlife:warn:inactive:expires:

user

Username (as in /etc/passwd).

pwd

Encoded password.

changed

Last password change (Unix date format).

minlife

Minimum number of days a user must keep a new password.

maxlife

Maximum password lifetime, in days.

warn

Days to warn in advance of an upcoming password expiration.

inactive

Days after password expiration that the account will be disabled.

expires

Date the account expires (Unix date format).

/etc/master.passwd (FreeBSD)

user:pwd:UID:GID:class:pwd-expire:acct-expire:user-info:...

This file, which serves as both passwd and shadow files, uses three additional fields between the GID and user information fields:

pwd

Encoded password.

class

User class (see FreeBSD user classes).

pwd-expire

Password expiration date (Unix date format).

acct-expire

Account expiration date (Unix date format).

/etc/security/passwd (AIX)

Encoded passwords are stored in the password field.

/etc/group

The group file

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Process and Resource Management

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Job control

command &

Run the specified command in the background.

^Z

Stop foreground process.

jobs

List background processes.

fg [job]bg [job]

Resume the specified job in the foreground/background. job defaults to the stopped foreground job. %n refers to background job n. %?str refers to the background job whose command string contains the specified character string.

~^Z

Suspend an rlogin session. Add an additional tilde for each level of nesting (e.g., ~~^Z suspends a second-level rlogin session back to the first-level rlogin session, while ~^Z suspends the second-level session back to the local session).

ps

ps aux AIX, FreeBSD, Linux /usr/ucb/ps aux Solaris ps -elf System V version: HP-UX

Display the detailed process list. The al option to the first two commands produces a different listing, which displays the process priority and nice number.

ps output columns

USER (HP-UX: UID)

Username of the process owner

PID

Process ID

%CPU

Estimated fraction of CPU consumed (FreeBSD); CPU time/elapsed time (AIX, Solaris, Linux).

%MEM

Estimated fraction of consumed system memory

SZ

Virtual memory used, in KB (HP-UX: pages)

RSS

Physical memory used, in KB

TT (HP-UX: TTY)

TTY associated with the process

STAT (HP-UX: S)

Current process state flag(s):

R

Running or runnable

S

Sleeping

I

Idle (HP-UX: intermediate state)

T

Stopped

Z

Zombie process

D

Disk wait (not HP-UX)

X

Growing: waiting for memory (HP-UX)

K

Available kernel process (AIX)

W

Swapped out (not HP-UX)

N

Niced down (not HP-UX)

<

Niced: priority artificially raised (not HP-UX)

TIME

Total CPU time used

COMMAND

Command line being executed (truncated)

STARTED (HP-UX: STIME)

Time or date the process started

F

Flags associated with the process (see the psmanual page)

PPID

Parent's PID

NI

Process nice number

CP (HP-UX: C)

Short term CPU-use factor; used by the scheduler for computing the execution priority (PRI)

PRI

Actual execution priority (recomputed dynamically)

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Filesystems and Disks

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/etc/fstab

location mount-dir fs-type dump-freq fsck-pass options

Filesystem configuration file.

special-file

Filesystem location. For traditional local filesystems, this is the partition's block special file. A logical volume may also be specified if an LVM is in use. ForNFS remote filesystems, the format is host:/path.

For Samba filesystems, the Linux format is //host/share. The FreeBSD format is //user@host/share.

mount-dir

Directory where the filesystem will be mounted.

fs-type

Filesystem type keyword.

dump-freq

Integer indicating the frequency this filesystem should be backed up by the dump utility.

fsck-pass

Integer indicating the order fsck should check filesystems.

options

Comma-separated list of options or the keyword defaults.

/etc/vfstab (Solaris)

block-dev char-dev mt-dir fs-type fsck-pass auto? opts

Similar syntax to the tradition fstab file, except:

• Both block (for mounting) and character (for fcsk) special files are listed as the first two fields.
• auto? is either yes or no, depending on whether the filesystem should be mounted automatically at boot time with mount -a.
• The dump frequency field is not included.

/etc/filesystems (AIX)

mount-pt: attribute = value ...

Attributes

dev = /dev/logical-volume

Logical volume.

vol = "name"

Descriptive label.

vfs = jfs2

Filesystem type: jfs2 for local, nfs for NFS.

log = /dev/log-vol

Device to use for filesystem log.

mount = true|false

Mount automatically?

check = n

Sets the fsck pass.

options = list

Mount options.

quota = keywords

userquota and groupquota enable user and group disk quotas.

Filesystem types

Local

AIX:

jfs2

FreeBSD:

ufsHP-UX: vxfs, hfs

Linux:

ext2, ext3, reiserfs

Solaris:

ufs

CD-ROM

AIX:

cdrfs

FreeBSD:

cd9660HP-UX: cdfs

Linux:

iso9660

Solaris:

hsfs

DOS

FreeBSD:

msdos

Linux:

msdos

Solaris:

pcfs

Samba

FreeBSD:

smbfs

Linux:

smbfs

Filesystem mounting options

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Printing

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Printing subsystem components

Spool directories

AIX:

/var/spool/lpd/qdir and /var/spool/qdaemon

FreeBSD:

/var/spool/output/lpd/*

HP-UX:

/var/spool/lp/request/*

Linux:

/var/spool/lpd/*

Solaris:

/var/spool/lp/requests/*

Configuration file(s)

AIX:

/etc/qconfig

FreeBSD:

/etc/printcap

HP-UX:

/etc/lp/*

Linux:

/etc/printcap

Solaris:

/etc/lp/* and /etc/printers.conf

Boot script configuration

FreeBSD:

/etc/rc.conf: lpd_enable="YES"

HP-UX:

/etc/rc.config.d/lp: LP=1

SuSE Linux:

/etc/sysconfig/printer: DEFAULT_PRINTER=name

Used by FreeBSD and some Linux systems.

lpq

lpq [-P printer | -a]

List the contents of the default queue (no options), specified queue, or all queues.

lprm

lprm [-P printer] list

Remove print jobs from a queue. list can contain print-job IDs and/or usernames (remove all jobs owned by the specified user); if list is a single hyphen, all jobs are removed from the specified queue.

lpc

lpc [subcommand args]

Administrative utility. Executes the specified subcommand, or enters interactive mode if no subcommand is specified.

Subcommands

status printer

Display status of the line printer daemon and the specified print queue.

start printer

Restart printing on the printer after an abort or stop command.

stop printer

Stop all printing on printer after the current job has finished (new jobs are still accepted).

abort printer

Stop all printing on printer immediately (new jobs are still accepted).

clean printer

Remove all jobs from the printer's queue. The current job will still complete.

disable printer

Prevent users from adding new jobs to the specified queue (printing continues).

enable printer

Allow users to spool jobs to the queue.

down printer

Stop printing and disable the queue for printer (disable plus stop).

up printer

Enable the queue and start printing on printer (enable plus start).

topq printer job-ID

Move the specified job to the top of the queue.

LPRng enhancements to lpc

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Serial Lines

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Termcap/terminfo file

AIX:

/usr/lib/terminfo

FreeBSD:

/etc/termcap (a link to /usr/share/misc/termcap)

Linux:

/etc/termcap and /usr/share/terminfo

HP-UX:

/usr/lib/terminfo (a link to /usr/share/lib/terminfo)

Solaris:

/etc/termcap and /usr/share/lib/terminfo

stty

stty options [value] ...

Modify serial line settings.

Options

n

Baud rate.

rows n

Lines on the screen.

columns n

Columns on the screen.

[-]echo

Echo/don't echo typed characters on the screen.

erase c

Delete the previous character.

kill c

Erase the entire command line.

intr c

Interrupt the foreground command.

eof c

End-of-file signal.

susp c

Suspend the foreground command.

lnext c

Interpret the next character literally (used to insert control characters into the command line).

werase c

Erase the previous word.

rprnt c

Reprint the pending command line.

stop c

Pause terminal input and output.

start c

Restart a paused terminal.

flush c

Discard all pending (undisplayed) output.

quit c

Kill the foreground command and dump core.

oddp

Enable odd parity.

evenp

Enable even parity.

-parity

No parity is generated or detected.

cstopb

Use two stop bits (-cstopb means one stop bit).

clocal

Use a hard carrier (-clocal means soft).

sane

Reset many options to reasonable settings.

/etc/ttys (FreeBSD)

port command type [flags]

port

Special file in /dev that communicates with this serial line.

"command"

getty command init should run for this serial line.

type

Terminal type (from /etc/termcap), the network keyword (for pseudo terminals), or dialin (for dial-up modems).

flags

Keywords, separated by spaces:

on|off		Is line enabled?
secure		Allow root logins.
window=cmd	init should run cmd before the command in field 2.
group=name	Define group of teminals for /etc/login.conf.

/etc/inittab (AIX, HP-UX, Linux, Solaris)

Terminal-related entries have a gettycommand as their final field (see Section for more about the inittab file).

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Networking

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ifconfig

ifconfig lo0 localhost up ifconfig interface ip-address netmask mask

The first form configures the loopback interface. The second form assigns the specified IPv4 address and subnet mask to interface. FreeBSD and Solaris allow you to replace the address and netmask parameters (including the keywords) with a CIDR address.

Displaying information about network interfaces

ifconfig [options] [interface]

Display the configuration of the specified interface(s).

-a

Display data for all interfaces (not supported by HP-UX).

-l (FreeBSD and AIX)

List all network interfaces.

Network interface configuration files

AIX

Stored in the ODM; modify with mktcpip or SMIT.

FreeBSD

/etc/rc.conf:

hostname="name"
ifconfig_iface="ip-addr netmask mask" 

HP-UX

/etc/rc.config.d/netconf:

HOSTNAME="name" 
INTERFACE_NAME[n]=name
IP_ADDRESS[n]=addr
SUBNET_MASK[n]=mask
INTERFACE_STATE[n]=up|down

n is the interface number (starting at 0).

Linux

/etc/sysconfig/networking/devices/ifcfg-ethn Red Hat

/etc/sysconfig/network/ifcfg-ethn SuSE

DEVICE=name 		Red Hat
BOOTPROTO=static|dhcp
IPADDR=addr
NETMASK=mask
ONBOOT=yes|no 				Red Hat only
STARTMODE=yes|no 		        SuSE only

/etc/sysconfig/network: Red Hat

HOSTNAME="name"					

/etc/HOSTNAME:

Holds the hostname (SuSE).

Solaris

/etc/hostname.iface:

The first line holds the hostname. Any additional line(s) hold ifconfig command arguments (optional).

Displaying the system's MAC address

AIX:

entstat adapter

HP-UX:

lanscan

FreeBSD, Linux, Solaris:

ifconfig interface

CIDR suffixes and subnet masks

Suffix	Subnet mask	Max. hosts
/22	255.255.252.0	1022
/23	255.255.254.0	510
/24	255.255.255.0	254
/25	255.255.255.128	126
/26	255.255.255.192	62
/27	255.255.255.224	30
/28	255.255.255.240	14
/29	255.255.255.248	6
/30	255.255.255.252	2

Important services and their associated ports

Unless otherwise noted,services are assigned to both the TCP and UPD ports; port numbers followed by an "s" are used by the secure version of the service.

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/etc/aliases file

alias: name [name ...]

Define a mail alias as the specified list of user(s) and/or other aliases. Aliases can be nested. An initial backslash defines a terminal alias (not subject to further expansion).

This file is stored in /etc/mail/aliases under FreeBSD and HP-UX.

File/directory locations

Boot script configuration file

FreeBSD

/etc/rc.conf:

sendmail_enable="YES"

HP-UX

/etc/rc.config.d/mailservs:

export SENDMAIL_SERVER=1

Linux

/etc/sysconfig/sendmail:

START_SENDMAIL="yes"

Solaris

/etc/default/sendmail:

DAEMON=yes

sendmail.cf directory

Usual:

/etc/mail

AIX:

/etc

Linux:

/etc

Configuration file build area

AIX:

/usr/samples/tcpip/sendmail/cf

FreeBSD:

/usr/share/sendmail/cf/cf

HP-UX:

/usr/newconfig/etc/mail/cf/cf

Linux:

/usr/share/sendmail-cf/cf (Red Hat) /usr/share/sendmail/cf (SuSE)

Solaris: