useful ALOM/SC console commands

ALOM commands:
==============

connecting console

sc>console
sc>console -f
sc>#.            ---> to exit console use(OS prompt)



sc>setsc_escapchars #.    ---> to set escape character to #. to exit console

sc>logout ---> to exit from console



System info:-
------------

sc>showplatform     ----> check HW maodel and domain status
sc>showenvironment  ----> Check sensor values
sc>showfru          ----> FRUID/FRU prom
sc>showsc           ---->Display details of sc software config

Network commands:-
-----------------

Setup ALOM IP address:

sc>setsc set if_network true
sc>setsc netsc_dhcp false
sc>setsc netsc_ipaddr 192.168.1.132
sc>setsc netsc_ipnetmask 255.255.255.0
sc>setsc netsc_ipgateway 192.168.1.1
sc>resetsc

sc>shownetwork -v     ----> Display current netwoek config



sc>showuses    --> list available users

sc>userpassword username   --->set/reset userpasswd
sc>password    ---> change own password
sc>usershow username ----> to details about user


power management:

sc>poweron
sc>poweroff
sc>reset
sc>break    ----> send break signal to OS




logs:

sc>showlogs -v
sc>consolehistory

Server Locator:

sc>showlocator
sc>setlocator on/off

sc>dumpconfig -s ipaddr -f pathname     ---->save your current ALOM configuration to a remote file server using FTP

Firmware upgrade:-
-----------------

sc>flashupdate -s ipaddr -f pathname/alomfw      ---> to update single ALOM firmware image
sc>flashupdate -s ipaddr -f pathname/alommainfw  --->For the main firmware image
sc>flashupdate -s ipaddr -f pathname/alombootfw  ---> For the boot monitor image
sc>resetsc

eg:


sc> flashupdate -s xxx.xxx.xxx.xxx -f
/usr/platform/SUNW,Netrax40/lib/images/alommainfw
Username: joeuser
Password: ********
..........................
Update complete. To use the new image the device will need to be reset using 'resetsc'.
sc>


OS commands for ALOM  :-


# cd /usr/platform/`uname -i`/sbin/scadm         (path of scadm command)
# scadm resetrsc [-s]       [ -s for soft reset ]
# scadm set [variable] [value]
# scadm show [variable]
# scadm useradd user_name
# scadm userdel user_name
# scadm usershow user_name
# scadm userpassword user_name
# scadm userperm user_name
# scadm shownetwork
# scadm consolehistory -a
# scadm loghistory -a
# scadm version -v


c> help
Available commands
---------------------
poweron [-c] {FRU}
poweroff [-y] [-f]
removefru [-y] {FRU}
reset [-y] [-x] [-c]
break [-y] [-c]
bootmode [normal|reset_nvram|diag|skip_diag|bootscript="string"]
console [-f]
consolehistory [-b lines|-e lines|-v] [-g lines] [-p|boot|run]
dumpconfig [-t] -s <IPaddr> -f <pathname>
showlogs [-b lines|-e lines] [-g lines] [-v] [-p logtype[r|p]]
setlocator [on|off]
showlocator
showenvironment
setfru -c <Customer data>
showfru [-g lines] [-s|-d] [FRU]
showplatform [-v]
setkeyswitch [-y] [normal|stby|diag|locked]
showkeyswitch
showsc [-v] [param]
shownetwork [-v]
setsc [-r [y]] [param] [value]
ssh-keygen [-t rsa|dsa] [-r] [-l]
restartssh [-y |-n]
setupsc
showdate
setdate [[mmdd] HHMM | mmddHHMM[cc]yy] [.SS]
resetsc [-y]
restoreconfig [-t] [-x] [-y] -s <IPaddr> -f <pathname>
flashupdate -s <IPaddr> -f <pathname> [-v]
setdefaults [-y] [-a]
useradd <username>
userdel [-y] <username>
usershow [username]
userpassword <username>
userperm <username> [c] [u] [a] [r]
password
showusers [-g lines]
logout
help [command]
sc>

Useful XSCF commands

XSCFCommands:-
=============


showdomainstatus

console -d 00

poweron -a

poweron -d 0

poweroff -a

poweroff -d 0

rebootxscf



reset -d 0 por

reset -d 0 panic
reset -d 0 xir


sendbreak -d 0

showuser -a

shownetwork -a

cfgdevice -l ---> list attached device


showhostname -a

sethostname xscf#0 hostname

sethostname -d example.com


setnetwork xscf#0-lan#0 -m 255.255.255.0 192.168.1.22


applynetwork

rebootxscf


Hardware Info:-
------------------
showstatus

showhardconf

showdevices


fmdump -v

fmdump -e -V -u <UUID>

showlogs -v
showlogs error
showlogs power

Take snapshot :-

snapshot -L F -d username@servername:/var/tmp

Solaris Administrator Interview Questions

1.Is it possible to change the M series processor to T series server ?
2.Difference Control domain vs IO domain?
3.How to replace HBA card in T series And what will be impact and how resolve those?
4.How to replace PCI card in M9k? process vise
5.How to break the servers T-series
6.How view the entire ldom console logs?
7./etc/system set max user value purpose?
8.Application team is starting app's they are gettig error no device space avalibale but application mount point has enough space?
9.How take ldom configuration backup?
10.how take backup of all ldom's?
11.Which multi path will recommend to storage  for better perfoemance in Hittachi ,IBM ?
12.How will you confirm multipath enabled or not?
13.How will confirm IPMP is working ?
14.how to do DC migration ,how will you backup of FS?
15.What is the private & public region in VXVm?
16.When public and private region gets' created in VXVM ?
17.How to take backup of particular volume in VXVM?
18.There 2 plex in volume 1 got failed is there any impact of volume and data ?
19.what is mean by plesx status "tmp_recovery"?
20.There are multiple volume in Diskgroup ,1 disk got failed on DG ,no layout,volume not mounted .what is the impact of data & volume?
21.how to send  break to server in ILOM ?
22.how to take snapshot in T-series ?
23.how to panic the server?
24.what is the jeopardy in vcs?
25.how to create raw data set in ZFS ?
26.How to take clone in ZFS?
27.How to recover the ldom's useing sp-conifg ?
28.Do you share the root password to oracle ?

Procedure To Configure a Whole Root Zone on Solaris 10

Steps:-

1.Start the zone configuration.

#zonecfg -z wholerootzone, where wholerootzone is the name of the new whole root zone.

Create a configuration for the specified zone.

zonecfg:wholerootzone> create -b

2.Set the zone path.

The zone path must specify a highly available local file system. The file system must be managed by the SUNW.HAStoragePlus resource.

zonecfg:wholerootzone> set zonepath=/global/zones/HA/wholerootzone (Any local filesystem which has enough space to host)

3.Set the autoboot value.

If the autoboot value is set to true, the zone is automatically booted when the global zone is booted. The default value is false.

zonecfg:wholerootzone> set autoboot=false

If resource pools are enabled on the system, associate a pool with the zone.

zonecfg:wholerootzone> set pool=pool_default, where pool_default is the name of the resource pool on the system.

4.Add a network virtual interface.

zonecfg:wholerootzone> add net

5.Set the IP address for the network interface.

zonecfg:wholerootzone> set address=10.255.255.255

6.Set the physical device type for the network interface.

zonecfg:wholerootzone> set physical=hme0

zonecfg:wholerootzone> end

7.Verify and commit the zone configuration.

zonecfg:wholerootzone> verify

zonecfg:wholerootzone> commit

zonecfg:wholerootzone> exit

Solaris LDOM useful commands

ldm ls-devices -a  ---> To List I/O device on control domain.
ldm ls-services    ---> To list available Virtual services on control domain
ldm ls ---> To list ldom's

ldm ls-bindings primary
ldm set-mau 1 primary

ldm set-vcpu 8 primary ---> Adding  vcpu to ldom
ldm set-mem 16g primary ---->Assigning memory to ldom
ldm add-config base   --> Save  sp-configuration file
ldm ls-config    ---> to list sp-config
ldm -V   ---> list the hypervisor version
virtinfo -a   ---> To check control domain name on ldom


Ldom  creation :-
================

ldm add-domain ldom1

ldm ls-domain

ldm add-memory 4g ldom1

ldm add-cpu 8 ldom1

ldm add-vnet vent0 primary-vsw0 ldom1

ldm ls-bindings ldom1

ldm add-vdsdev /dev/dsk/c1t1d0s2 ldom1-OS@primary-vds0

ldm ad-vdsik vdisk1 ldom1-OS@primary-vds0 ldom1


ldm add-vdsik cdrom  iso1@primary-vds0 ldom1

ldm ls-services

ldm ls-services vds0

ldm bind-domain ldom1

ldm set-variable auto-boot\?=false ldom1

ldm start ldom1

telnet 0 5002

Adding zfs data set to LDOM's:
==============================

zfs create -V 25G pool1/ldom1

ldm add-vdsdev /dev/zvol/dsk/pool1/ldom1 ldom1-app@primary-vdso

ldm add-vdisk vdisk2 ldom1-app@primary-vdso ldom1


Adding IsO to control domain:-
=============================


ls /export/home/sol1-10-u10-ga2-sparc-dvd.iso


ldm add-vdsdev options=ro /export/home/sol1-10-u10-ga2-sparc-dvd.iso iso2@primary-vds0


Removing service and domains:-
=============================

ldm stop-domain ldom1

ldm unbind-domain ldom1

ldm remove-domain ldom1


ldm remove-vdisk vdisk1 ldom1
ldm remove-vdisk vdisk ldom1


ldm ls-services

ldm remove-vdsdev ldom1-os@primary-vdso
ldm remove-vdsdev ldom1-app@primary-vdso


LDOM configuration Backup and Restore:-
======================================

ldm ls-config

ldm ls-constraints -x >config .xml

ldm ls-contraints -x ldom1 > ldom1.xml



ldm ls-config

ldm rm-config baseconfig

powercycle
=====================================================================
Once the system has restored to the factory default,then you can restore the system backup using the XML files which we have created.
Login to the control domain and restore it.
=====================================================================

ldm init-system -i config.xml

ldm add-config baseconfig2

#ldm ls-config
factory-default
baseconfig
baseconfig2


ldm init-system -i ldom1.xml -----> only particular ldom restore

ldom add-config baseconfig3

Some Useful Solaris Study Links

1.http://www.googlux.com/index.htm

How to take snapshot from SPARC xscf console

XSCF> snapshot -L F -t username@10.140.0.21:/tmp/mark

How to Access (Root) Disk under Solaris Volume Manager Control (SVM) from Failsafe or CDROM and Update the boot_archive in Solaris 10

The following procedure describes how to fsck and mount a mirrored metadevice during a failsafe boot. In this procedure, the root (/) file system that is used is /dev/dsk/c0t0d0s0.

Boot the failsafe archive.

SPARC platform: From the ok prompt, type the following command:

ok boot -F failsafe

If the system is already running, open a terminal window, become superuser, and type the following command:

# reboot -- "-F failsafe"

Note: Do not get the boot_archive updated automatically in this step. It would destroy the consistency of your mirror.

Booting the system in failsafe mode produces the following output:

Starting shell. #

During the failsafe boot, when prompted by the system to select a device to mount, type q to indicate none:

Please select a device to be mounted (q for none)[?,??,q]: q

Temporarily mount a submirror of the root (/) file system as read-only on the /a directory:

# mount -o ro /dev/dsk/c0t0d0s0 /a

Copy the md.conf file to the /kernel/drv directory:

# cp /a/kernel/drv/md.conf /kernel/drv/

Cat the vfstab file to identify the root disk, /var, /usr file systems, etc:

# cat /a/etc/vfstab

Unmount the /a directory:

# umount /a

Use the update_drv command to load the Solaris Volume Manager md driver. Ignore any warning messages printed by the update_drv command:

# update_drv -f md

Running the update_drv command causes the configuration to be read, and the necessary devices to be created.

Use metastat to confirm that the SVM database has been loaded:

# metastat -p

Note: You might have to wait a few seconds (up to a minute) before the metastat command executes successfully. The md driver takes some time to load its configuration. If you are too quick, the metastat (and metasync) commands will give you an error message. Just wait some more seconds in this case and execute the metastat or metasync commands again.

Use the metasync command to ensure that the root (/) file system is in sync:

# metasync d0

Now fsck can be safely run on d0:

# fsck -o f -y /dev/md/rdsk/d0

Please repeat this command if any file system errors were fixed. You have to repeat it until the file system is clean. This can take 3 or 4 runs of fsck command.
Force option -o f prevents fsck from skipping the file system check. It is recommended to use option -y as well to confirm all changes to the file system.

Mount the root mirror metadevice on the /a directory:

# mount /dev/md/dsk/d0 /a

Note: If you have separate usr or var file systems repeat the previous fsck step for the corresponding meta devices for /usr and /var and mount the file systems to /a/usr and /a/var respectively.

Update the boot archive:

# bootadm update-archive -v -R /a

If the boot archive fails to be updated, or an error message is displayed, update the timestamp on the /a/kernel/drv/md.conf file, then run bootadm update-archive again.
This will force an update of the boot archive:

# touch /a/kernel/drv/md.conf

# bootadm update-archive -v -R /a

The update of the boot archive takes a few minutes to complete. If the boot archive was updated successfully, a message similar to the following is displayed:

changed /a/etc/system

cannot find: /a/etc/cluster/nodeid: No such file or directory

cannot find: /a/etc/devices/mdi_ib_cache: No such file or directory

Creating ram disk on /a updating /a/platform/i86pc/boot_archive

This is expected output and does not constitute an error.

These messages are a result of entries in /boot/solaris/filelist.ramdisk , which may or may not exist on system.

# less /boot/solaris/filelist.ramdisk

etc/cluster/nodeid

etc/dacf.conf

etc/mach

kernel

platform

Unmount all previously mounted file systems /a/var, /a/usr and /a:

# umount /a/var

# umount /a/usr

# umount /a

Reboot the system:

# reboot

Taking Solaris 11 rpool snapshot image (Flar Archive) for Installation purpose

Solaris 11 Taking rpool zfs snapshot image (Flar archive):
----------------------------------------------------------------------


Taking snapshot of rpool.

 #zfs snapshot -r rpool@Solaris11_3


We can remove swap and core dump dataset from rpool snapshot to maintain the OS image size.

#zfs destroy rpool/swap@Solaris11_3

#zfs destroy rpool/dump@Solaris11_3

Taking image and storing on shared path:

#zfs send -Rv rpool@Solaris11_3 | gzip | ssh root@191.168.28.54 "cat > /Flar/rpool_Solaris11_3_$(hostname)_$(date +%Y%m%d).zfs.gz"

After Kernel Patching in RHEL 5 Servers VXFS mount point missing

#vxdctl mode
vxdctl -not running
#vxdctl enable - if enable not happening

cd /etc/rc2.d/
./S00vxvm-boot start
./S00vxfs start

maximum it will get resolved
#df -h --it will show vxfs get mounted


other issues:-

Solaris Performance Monitoring & Tuning

Introduction to iostat , vmstat and netstat 

                                                  This document is primarily written with reference to Solaris performance monitoring and tuning but these tools are available in other Unix variants also with slight syntax difference.
 iostat , vmstat and netstat are three most commonly used tools  for performance monitoring . These comes built in with the operating system and are easy to use .iostat stands for input output statistics and reports statistics for i/o devices such as disk drives . vmstat  gives  the statistics for virtual Memory and netstat gives the network statistics .

Input Output statistics (  iostat )  iostat   reports terminal and disk  I/O  activity and  CPU utilization.  The first line of output is for the  time period  since boot  &  each subsequent line is for  the  prior  interval . Kernel maintains  a number of counters to keep track of  the  values. iostat's activity class options default  to  tdc  (terminal,  disk, and CPU). If any other option/s are specified,  this  default is completely overridden i.e.  iostat -d will report only statistics about the disks. syntax: Basic synctax is iostat  <options>   interval  count option - let you specify the device for which information is needed like disk , cpu or terminal. (-d , -c , -t  or -tdc ) .  x options gives the extended statistics . interval -  is time period in seconds between two samples . iostat  4  will give data at each 4 seconds interval. count  - is the  number of times the data is needed .  iostat 4 5   will give data at 4 seconds interval   5 times

Example

$ iostat -xtc 5 2                           extended disk statistics       tty         cpu      disk r/s  w/s Kr/s Kw/s wait actv svc_t  %w  %b  tin tout us sy wt id      sd0   2.6 3.0 20.7 22.7 0.1  0.2  59.2   6   19   0   84  3  85 11 0      sd1   4.2 1.0 33.5  8.0 0.0  0.2  47.2   2   23      sd2   0.0 0.0  0.0  0.0 0.0  0.0   0.0   0    0      sd3  10.2 1.6 51.4 12.8 0.1  0.3  31.2   3   31      The fields have the following meanings:       disk    name of the disk       r/s     reads per second       w/s     writes per second       Kr/s    kilobytes read per second       Kw/s    kilobytes written per second       wait    average number of transactions waiting for service (Q length)       actv    average number of transactions  actively                being serviced (removed  from  the               queue but not yet               completed)       %w      percent of time there are transactions  waiting               for service (queue non-empty)       %b      percent of time the disk is busy  (transactions                   in progress)

Results and Solutions:

The values to look from the iostat output  are:

• Reads/writes  per second (r/s , w/s)
• Percentage busy (%b)
• Service time (svc_t)

If a disk shows consistently high reads/writes along with , the percentage busy (%b) of the disks is greater than 5 percent, and the average service time  (svc_t) is greater than 30 milliseconds, then  one of the following action needs to be taken

1.)Tune the application to use disk i/o more efficiently  by modifying the disk queries and using available cache facilities of application servers .

2.) Spread the file system of the disk on to two or more disk  using disk striping feature of volume manager /disksuite  etc.

3.) Increase the system parameter values for  inode cache  , ufs_ninode ,  which is  Number of inodes to be held in memory. Inodes are cached globally (for UFS), not on a per-file system basis 

4.) Move the file system to another faster disk /controller  or replace existing disk/controller to a faster

     one.

---

Virtual Memory Statistics ( vmstat )

vmstat -  vmstat reports virtual memory statistics of   process, virtual memory, disk, trap, and CPU activity.

 On multicpu systems , vmstat averages the number of CPUs  into  the  output. For per-process statistics .Without options, vmstat displays a one-line summary  of  the  virtual memory activity since the system was booted.

 syntax:

Basic synctax is vmstat  <options>   interval  count

option - let you specify the type of information needed such as paging  -p , cache   -c ,.interrupt -i  etc.

if no option is specified  information about   process , memory , paging , disk ,interrupts & cpu  is displayed  .

interval  - is time period in seconds between two samples . vmstat   4  will give data at each 4 seconds interval.

count  - is the number of times the data is needed . vmstat 4   5   will give data at 4 seconds interval   5

             times.

 Example

     The following command displays a summary of what the  system

     is doing every five seconds.

     example% vmstat 5

procs  memory          page             disk      faults        cpu      r b w swap  free re mf pi p fr de sr s0 s1 s2 s3  in  sy  cs us sy id      0 0 0 11456 4120 1  41 19 1  3  0  2  0  4  0  0  48 112 130  4 14 82      0 0 1 10132 4280 0   4 44 0  0  0  0  0 23  0  0 211 230 144  3 35 62      0 0 1 10132 4616 0   0 20 0  0  0  0  0 19  0  0 150 172 146  3 33 64      0 0 1 10132 5292 0   0  9 0  0  0  0  0 21  0  0 165 105 130  1 21 78

 The fields of vmstat's display are
     procs
             r     in run queue
             b     blocked for resources I/O, paging etc.
            w     swapped

     memory (in Kbytes)
              swap -  amount  of  swap   space   currently   available               
              free   - size of the free list

     page ( in units per second).
           re    page reclaims -  see  -S  option  for  how  this field is modified.
           mf    minor faults -  see  -S  option  for  how    this field is modified.
           pi    kilobytes paged in
           po    kilobytes paged out
           fr    kilobytes freed
           de    anticipated short-term memory shortfall (Kbytes)
           sr    pages scanned by clock algorithm

     disk  ( operations per second )

           There are  slots for up to four disks, labeled with a single letter and number.

           The letter indicates  the  type  of  disk  (s = SCSI, i = IPI, etc) . The number is 

           the logical unit number.

     faults
            in    (non clock) device interrupts
           sy    system calls
           cs    CPU context switches

     cpu  -   breakdown of percentage usage of CPU  time.  On multiprocessors  this is an a

                verage across all processors.
           us    user time
           sy    system time
           id    idle time
 

Results and Solutions:

A.   CPU issues:

Following columns has to be watched to determine if there is any cpu issue

1. Processes in the run queue (procs r)
2. User time (cpu us)
3. System time (cpu sy)
4. Idle time (cpu id)

procs      cpu      r b w    us sy  id      0 0 0    4  14  82      0 0 1    3  35  62      0 0 1    3  33  64      0 0 1    1  21  78

Problem symptoms:

1.) If the number of processes in run queue (procs r) are consistently greater than the number of CPUs on the system it will slow down system as there are more processes then available CPUs .

2.) if  this number is more than four times the number of available CPUs in the system then system is facing shortage of cpu power and will greatly slow down the processess on the system.

3.) If  the idle time (cpu id) is consistently 0 and if the system time (cpu sy) is double the user time (cpu us)  system is facing shortage of CPU resources.

 

Resolution :

Resolution to these kind of issues involves tuning of application procedures  to make efficient use of cpu  and as a last resort increasing the cpu power or adding more cpu to the system.  

 

 

B.   Memory Issues:

Memory bottlenecks are determined by the scan rate (sr) . The scan rate is the pages scanned by the clock algorithm per second. If the scan rate (sr) is continuously over 200 pages per second then there is a memory shortage.

 

Resolution :

1. Tune the applications & servers to make  efficient use of memory and cache.

2. Increase system memory .

3. Implement priority paging in s in pre solaris 8 versions by adding line "set priority paging=1" in

    /etc/system. Remove this line if upgrading from Solaris 7 to 8 & retaining old /etc/system file.

---

Network Statistics (netstat)

netstat displays the  contents  of  various  network-related  data structures in  depending on the options selected.

Syntax :

netstat  <option/s>

multiple options can be given at one time.

Options

 -a - displays the state of all sockets.
 -r - shows the system routing tables
 -i - gives statistics on a per-interface basis.
-m - displays information from the network memory buffers. On Solaris, this shows statistics

         forSTREAMS
 -p [proto] - retrieves statistics for the specified protocol
  -s - shows per-protocol statistics. (some implementations allow -ss to remove fileds with a value of 0 (zero) from the display.)
 -D - display the status of DHCP configured interfaces.
-n do not lookup hostnames, display only IP addresses.

-d (with -i) displays dropped packets per interface.

-I [interface] retrieve information about only the specified interface.

-v be verbose

interval  -   number for continuous display of statictics.

Example :

$netstat -rn Routing Table: IPv4   Destination           Gateway               Flags  Ref   Use   Interface -------------------- -------------------- ----- ----- ------ --------- 192.168.1.0         192.168.1.11           U        1   1444      le0 224.0.0.0             192.168.1.11           U        1   0            le0 default                  192.168.1.1           UG       1   68276  127.0.0.1             127.0.0.1               UH       1  10497     lo0

This shows the output on a Solaris machine who's IP address is 192.168.1.11 with a default router at 192.168.1.1

Results and Solutions:

A.) Network availability

The command as above is mostly useful in troubleshooting network accessibility issues . When  outside network is not accessible from a machine check the following

1. if the default router ip  address is correct

2.  you can ping it from your machine.

3. If router address is incorrect  it can be changed  with route add  commnad . See man route  for more info .

route command examples:
$route add default <hostname>

$route add 192.0.2.32  <gateway_name>

If the router address is correct but still you can't ping it  there may be some  network cable /hub/switch problem  and you have to try and eliminate the faulty component .

B.) Network Response

$ netstat -i

Name	Mtu	Net/Dest	Address	Ipkts	Ierrs	Opkts	Oerrs	Collis	Queue
lo0	8232	loopback	localhost	77814	0	77814	0	0	0
hme0	1500	server1	server1	10658566	3	4832511	0	279257	0

This option is used to diagnose the network problems when  the connectivity is there but  it is slow in response .

Values to look at:

• Collisions (Collis)
• Output packets (Opkts)
• Input errors (Ierrs)
• Input packets (Ipkts)

The above values will give information to workout

i.  Network collision rate as follows :

Network collision rate = Output collision counts / Output packets

 Network-wide collision rate greater than 10 percent  will indicate

•  Overloaded network,
•  Poorly configured network,
•  Hardware problems. 

ii.  Input packet error rate as follows :

 Input Packet Error Rate = Ierrs / Ipkts.

If the input error rate is high (over 0.25 percent), the host is dropping packets. Hub/switch cables etc needs to be checked for potential problems.

C.  Network socket &  TCP Cconnection state

Netstat gives important   information about network socket and tcp state . This is very useful in

finding out the open , closed and  waiting network tcp connection .

Network states returned by  netstat are following :

     CLOSED               ----  Closed.  The socket  is  not  being used.
     LISTEN                 ----  Listening for incoming connections.
     SYN_SENT           ----  Actively trying to  establish  connection.
     SYN_RECEIVED  ---- Initial synchronization of the connection under way.
     ESTABLISHED     ----  Connection has been established.
     CLOSE_WAIT      ----  Remote shut down; waiting  for  the socket to close.
     FIN_WAIT_1        ----  Socket closed; shutting  down  connection.
     CLOSING             ----  Closed,   then   remote   shutdown; awaiting acknowledgement.
     LAST_ACK          ----   Remote  shut  down,  then   closed ;awaiting acknowledgement.
     FIN_WAIT_2        ----  Socket closed; waiting for shutdown from remote.
     TIME_WAIT         ----  Wait after close for  remote  shutdown retransmission.
     

 

Example:

 #netstat -a

Local Address Remote Address Swind   Send-Q Rwind Recv-Q State  *.* *.* 0 0 24576 0 IDLE *.22 *.* 0 0 24576 0 LISTEN *.22 *.* 0 0 24576 0 LISTEN *.* *.* 0 0 24576 0 IDLE *.32771 *.* 0 0 24576 0 LISTEN *.4045 *.* 0 0 24576 0 LISTEN *.25 *.* 0 0 24576 0 LISTEN *.5987 *.* 0 0 24576 0 LISTEN *.898 *.* 0 0 24576 0 LISTEN *.32772 *.* 0 0 24576 0 LISTEN *.32775 *.* 0 0 24576 0 LISTEN *.32776 *.* 0 0 24576 0 LISTEN *.* *.* 0 0 24576 0 IDLE 192.168.1.184.22 192.168.1.186.50457 41992 0 24616 0 ESTABLISHED 192.168.1.184.22 192.168.1.186.56806 38912 0 24616 0 ESTABLISHED 192.168.1.184.22 192.168.1.183.58672 18048 0 24616 0 ESTABLISHED

if  you see a lots of connections in FIN_WAIT state  tcp/ip parameters   have to be tuned  because the

connections  are not being closed and they gets accumulating . After some time system may run out of

resource . TCP parameter can be tuned to define a time out so that connections can be released and

used by new connection.