==== Change IP adress on Suse using command line ====

<code>
ip a s 
ip r s
ip n s
</code>

/etc/sysconfig/network/ifcfg-eth0

Samples of proxy variables:
<code>
export http_proxy=http://10.203.0.1:5187/
export https_proxy=http://10.203.0.1:5187/
export ftp_proxy=http://10.203.0.1:5187/
export no_proxy="localhost,127.0.0.1,localaddress,.localdomain.com"
http_proxy=http://username:password@hostname:port
</code>

==== Remove virbr0 on Redhat ====

The virbr0 (bridge) is like a switch into which you can connect your virtual guests
and your host. The host can act as a router between outside physical subnet and
internal virtual subnet. The router can do NAT (aka masquerade).

{{:linux:virbr-nat.gif?450}}

Disable libvirtd default network
<cli>
# systemctl stop libvirtd.service
# systemctl disable libvirtd.service
# virsh net-destroy default
# virsh net-autostart default --disable
</cli>

Disable permanent
<cli>
# virsh net-undefine default
</cli>

Or use
<cli>
# brctl show
bridge name     bridge id                        STP enabled     interfaces
virbr0              8000.000000000000         no
</cli>
<cli>
# ip link set virbr0 down
# brctl delbr virbr0
</cli>
==== Disable IPv6 on Redhat ====

<cli prompt='#'>
[root@Centos64 ~]# vi /etc/modprobe.d/disable-ipv6.conf
install ipv6 /bin/true
[root@Centos64 ~]# vi /etc/sysconfig/network
NETWORKING=yes
NETWORKING_IPV6=no
HOSTNAME=Centos64
GATEWAY=192.168.0.1
[root@Centos64 ~]# echo “net.ipv6.conf.all.disable_ipv6 = 1″ >> /etc/sysctl.conf
</cli>

==== Add static routes permanent ====

/etc/sysconfig/network
  default via 192.168.1.1 dev eth0
  10.10.10.0/24 via 192.168.1.1 dev eth1
  10.10.11.0/24 via 192.168.11.1

/etc/sysconfig/network-scripts/route-eth0
  default via 192.168.0.1 dev eth0
  10.10.10.0/24 via 192.168.0.10 dev eth0
  172.16.1.10/32 via 192.168.0.10 dev eth0

==== Add static routes nonpersistent ====

To add or delete a route from the table, use the ip route add or ip route del commands. For example, to replace the entry for the static default route:
<cli prompt='#'>
# ip route del default
# ip route show
10.0.2.0/24 dev eth0  proto kernel  scope link  src 10.0.2.15 
# ip ro add default via 10.0.2.1 dev eth0 proto static
# ip route show
10.0.2.0/24 dev eth0  proto kernel  scope link  src 10.0.2.15  
default via 10.0.2.1 dev eth0  proto static 
</cli>

To add a route to the network 10.0.3.0/24 via 10.0.3.1 over interface eth1, and then delete that route:
<cli prompt='#'>
# ip route add 10.0.4.0/24 via 10.0.2.1 dev eth1
# ip route show
10.0.2.0/24 dev eth0  proto kernel  scope link  src 10.0.2.15 
10.0.3.0/24 via 10.0.3.1 dev eth1
default via 10.0.2.2 dev eth0  proto static 
# ip route del 10.0.3.0/24
# ip route show
10.0.2.0/24 dev eth0  proto kernel  scope link  src 10.0.2.15 
default via 10.0.2.2 dev eth0  proto static 
</cli>

The ip route get command is a useful feature that allows you to query the route on which the system will send packets to reach a specified IP address, for example:
<cli prompt='#'>
# ip route get 23.6.118.140
23.6.118.140 via 10.0.2.2 dev eth0  src 10.0.2.15 
    cache  mtu 1500 advmss 1460 hoplimit 64
</cli>

===== Rename a network device to eth0 =====

Edit kernel boot parameter.

Edit file **/etc/default/grub** and add net.ifnames=0 biosdevname=0 to line GRUB_CMDLINE_LINUX, for instance:
<cli prompt='#'>
GRUB_CMDLINE_LINUX=" crashkernel=auto net.ifnames=0 biosdevname=0 rhgb quiet"
</cli>
Regenerate a GRUB configuration file and overwrite existing one:
<cli prompt='#'>
# grub2-mkconfig -o /boot/grub2/grub.cfg
</cli>


Update the rules file:
<cli prompt='#'>
# vi /etc/udev/rules.d/70-persistent-net.rules :
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="12:91:0C:F9:B7:98", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"
</cli>

<cli prompt='#'>
# cd /etc/sysconfig/network-scripts/
# mv ifcfg-ens192 ifcfg-eth0
</cli>

<cli prompt='#'>
# vi ifcfg-eth0
DEVICE=eth0        ### Change it to new device name "eth0"
</cli>