redhat network Commands

copied it from linuxCmdNetwork.docx in laptop

===============Networking===============================

http://www.yolinux.com/TUTORIALS/LinuxTutorialNetworking.html

ifconfig -a

ifconfig eth1 up    --->  to activate eth1

ifconfig eth1 down    ---> to de activate the eth1

ifup bond1  ---->  to activate a bond

service network restart   ---->  to restart network service

service network status    ----->   status of the network devices

system-config-network  ---> command to configure the Ethernet

list the network  devices

lspci

lspci -tv

lspci |grep net

systool -c net

systool -c net -v |grep -v "00 00 00"|grep -v "0x000"

systool -c net -d eth6  -v |grep -v "00 00 00"|grep -v "0x000"

To see  speed of  a Interface

systool -c net -d eth6  -v |grep -v "00 00 00"|grep -v "0x000" |egrep "Class |speed"

systool -c net  -v |grep -v "00 00 00"|grep -v "0x000" |egrep "Class|speed"

grep -H .  /sys/class/net/*/speed

grep -H .  /sys/class/net/*/mtu

To  see  the   interface  and   network  slot  info

/opt/dell/srvadmin/bin/omreport  chassis  nics

2) to see  onboard  network ports using dmidecode

Use below command to see the BUS Address for Ethernet ports

dmidecode -t baseboard |egrep -i "Desig|Bus|type|status"

dmidecode -t baseboard |grep -B1 -A3 Ethernet |egrep -i "Desig|Bus|type|status"

Then use below command to see eth# in  each BUS

systool -c net

lspci -tv |grep net

3)To see PCI slot network ports using dmidecode

Use below command to see BUSAddress for PCI slots

            dmidecode -t slot |egrep "Desig|Bus|Current|Type"

Then use below command to see eth# in  each BUS

systool -c net

lspci -tv |grep net

To  assign ipaddress on  interface

ifconfig eth1  xx.xx.xx.xx  netmask  255.xxx.xxx.x  up

service network restart

$ cat /etc/sysconfig/network-scripts/ifcfg-bond0

DEVICE=bond0

IPADDR=167.143.186.235

NETMASK=255.255.254.0

GATEWAY=167.143.186.1

ONBOOT=yes

BOOTPROTO=none

USERCTL=no

# Added OPTS for RHEL6 (glh)

        BONDING_OPTS="miimon=100 mode=active-backup"

Set static route  via bond1  ip address

$ cat /etc/sysconfig/network-scripts/route-bond1

162.100.228.0/24  via   170.13.151.1  dev  bond1

130.29.230.0/24  via  170.13.151.1 dev bond1

Netstat command

netstat  -rn      >>  to see routing table       

route  -e      >>      to see routing table        

netstat  -in      >>  network statistics summary

netstat  -an     >>  this will list all ports and their status

cat  /proc/net/dev  >>  to see packet send/receive summary through diff interfaces

to See  ports Listening Status

            grep 9080  /etc/services

            glrpc           9080/tcp                # Groove GLRPC

            netstat -anp  |grep 9080
            netstat -an | grep 1002
            netstat -lpn  ==>  to list listening ports
            netstat -lpn  |grep 1002
            netstat  -tulpn  ==> tcp,udp  listening ports

     lsof -i tcp:1002
     lsof -i udp:1002
     lsof -i  :1002
     lsof  -i |grep  glrpc

     lsof |grep glrpc

            https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/3/html/Security_Guide/s1-server-ports.html 

 http://www.binarytides.com/linux-ss-command/    ss command  usage 
List all connections The simplest command is to list out all connections. $  ss  | less

change network interface names permanently in Linux

In /etc/udev/rules.d/70-persistent-net.rules, you can assign  device name to a particular MAC address.

find out the MAC address interface"grep -H . /sys/class/net/*/address"  , and then define the interface name to that MAC address in the following format.

# interface with MAC address "00:0c:29:43:28:11" will be assigned "eth0"                                                                            

SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:0c:29:43:28:11", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"

To see if an interface  have connection 

ethtool eth2

Settings for eth1:

        Supports Wake-on: g

        Wake-on: d

        Link detected: yes 

mii-tool -v

eth0: negotiated, link ok

To enable Jumbo frames in Linux

To set temporary

# ifconfig eth0 mtu 9000

To Make changes permanent:-Edit the network configuration file for eth0 interface - /etc/sysconfig/network-scripts/ifcfg-eth0 (CentOS / RHEL / Fedora Linux):

# vi /etc/sysconfig/network-scripts/ifcfg-eth0

Append the following configuration directive, which specifies the size of the frame in bytes:

MTU 9000

 Restart the Interface eth0:

 /etc/init.d/network restart   or service network restart

To confirm the MTU used between two specific devices. use ip command as follows:

# ip route get {IP-address}

# ip route get 192.168.1.1

Do Ping Test

# ping   -s 8192   -I <source interconnect IP address> <destination IP address>

Example:

# ping -s 8192 -I 198.18.0.38 198.18.0.39

To see the bonds and the   related  network adapers

cd /proc/net/bonding

ls

cat bond0 

cd /sys/class/net/

[root@dansrzd180 net]# ls

bond0  bond1  eth0  eth1  eth2  eth3  lo  sit0

Steps to make BONDS

doc-7944    (how to make bond  RH3)

doc-8108    what are diff modes

how to make bond in RH4

http://kbase.redhat.com/faq/docs/DOC-4284

http://www.cyberciti.biz/tips/linux-bond-or-team-multiple-network-interfaces-nic-into-single-interface.html

http://et.redhat.com/~jmh/docs/Xen_networking.pdf

remember to make backup of files being changed  before editing

step1 :- update   /etc/modprobe.conf   with proper entties as below

vi /etc/modprobe.conf 

alias bond0 bonding

options bonding miimon=100 mode=1 max_bonds=2

install bond0 /sbin/modprobe bonding --ignore-install bonding

alias bond1 bonding

install  bond1 /sbin/modprobe bonding -o bond1

step2:  create fcfg-eth1,fcfg-eth3 and ifcfg-bond1  with simillar entries like below in /etc/sysconfig/network-scripts

[root@dansrzd180 network-scripts]# cat ifcfg-eth1

DEVICE=eth1

BOOTPROTO=none

ONBOOT=yes

MASTER=bond1

SLAVE=yes

USERCTL=no

HWADDR=00:24:E8:64:62:53

[root@dansrzd180 network-scripts]# cat ifcfg-eth3

DEVICE=eth3

BOOTPROTO=none

ONBOOT=yes

MASTER=bond1

SLAVE=yes

USERCTL=no

HWADDR=00:15:17:BC:C5:BD

[root@dansrzd180 network-scripts]# cat ifcfg-bond1

DEVICE=bond1

IPADDR=10.28.130.40

NETMASK=255.255.255.0

GATEWAY=

ONBOOT=yes

BOOTPROTO=none

USERCTL=no

step3 :-

update  /etc/hosts  file with interconnect ipaddresses

restart the networks and bringup the bond1

modprobe bonding

service network restart

ifup bond1

Kernal Mudule Commands

lsmod |grep bond   

rmmod    modname

modprobe --show-depends bond1

depmod -a   (generate map files )

modprobe - program to add and remove modules from the Linux Kernel

  eg:-  modprobe  bonding  -o bond1

            ifconfig bond1 down  ; modprobe -r bond1

Configuring the Linux6 host for LACP bonding

step1:Linux Kernel Module Configuration

#/etc/modprobe.d/bonding.conf

alias bond0 bonding

options bond0 miimon=100 mode=4 lacp_rate=1

step2:set Linux Network file Configuration

# cat /etc/sysconfig/network-scripts/ifcfg-bond0

DEVICE=bond0

ONBOOT=yes

BOOTPROTO=none

IPADDR=10.29.194.99

NETMASK=255.255.255.0

GATEWAY=10.29.194.1

BONDING_OPTS="mode=4 miimon=100 lacp_rate=1"

 # cat /etc/sysconfig/network-scripts/ifcfg-eth4

DEVICE="eth4"

BOOTPROTO="none"

HWADDR="00:10:18:F3:B7:1C"

ONBOOT="yes"

MASTER=bond0

SLAVE=yes

# cat cat /etc/sysconfig/network-scripts/ifcfg-eth5

cat: cat: No such file or directory

DEVICE="eth5"

HWADDR="00:10:18:F3:B7:1E"

ONBOOT="yes"

MASTER=bond0

SLAVE=yes

Restart network

service network restart

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Set  the  tcp window size  

Method1

Add to  /etc/sysctl.conf  below values

# TCP buffers

net.core.rmem_max = 16777216

net.core.wmem_max = 16777216

# autotune TCP buffers

net.ipv4.tcp_rmem = 4096 87380 16777216

net.ipv4.tcp_wmem = 4096 65536 16777216

then do

sysctl  -p

Method 2

Command	Description
echo "1" > /proc/sys/net/ipv4/tcp_window_scaling	Activate window scaling according to RFC 1323
echo "1" > /proc/sys/net/ipv4/tcp_timestamps	Activate timestamps according to RFC 1323
echo [wmax] > /proc/sys/net/core/rmem_max	Set maximum size of TCP receive window.
echo [wmax] > /proc/sys/net/core/wmem_max	Set maximum size of TCP transmit window.
echo [wmax] > /proc/sys/net/core/rmem_default	Set default size of TCP receive window.
echo [wmax] > /proc/sys/net/core/wmem_default	Set default size of TCP transmit window.
echo "[wmin] [wstd] [wmax]" > /proc/sys/net/ipv4/tcp_rmem	Set min, default, max receive window. Used by the autotuning function.
echo "[wmin] [wstd] [wmax]" > /proc/sys/net/ipv4/tcp_wmem	Set min, default, max transmit window. Used by the autotuning function.
echo "bmin bdef bmax" > /proc/sys/net/ipv4/tcp_mem	Set maximum total TCP buffer-space allocatable. Used by the autotuning function.
ifconfig eth? txqueuelen 1000	Define length of transmit queue. Replace "?" with actual interface number.

Or 

sysctl -w "net.ipv4.tcp_window_scaling=0"

sysctl -w net.ipv4.tcp_congestion_control=cubic

TO see the kernel parameter value

sysctl  net.ipv4.tcp_window_scaling

To set the pagecache

echo "1 8 10" > /proc/sys/vm/pagecache

or

sysctl -w vm.pagecache="1 8 10"

or

echo "vm.pagecache=1 8 10" >> /etc/sysctl.conf

sysctl -p

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